ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2015

OR

¨

TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from
to

Commission File No. 0-21392

Amarin
Corporation plc

(Exact name of registrant as specified in its charter)

England and Wales

Not applicable

(State or other jurisdiction of

incorporation or organization)

(I.R.S. Employer

Identification No.)

2 Pembroke House

Upper Pembroke Street 28-32, Dublin 2, Ireland

(Address of principal
executive offices)

+353 (0) 1 6699 020

(Registrants telephone number, including area code)

Securities registered
pursuant to Section 12(b) of the Act:

Title of Each Class

Name of Each Exchange on Which Registered

American Depositary Shares, each representing one Ordinary Share

Ordinary Shares, 50 pence par value per share

The NASDAQ Stock Market LLC

Securities registered pursuant to Section 12(g) of the Act:

None

Indicate by
check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YES þ NO ¨

Indicate by check mark if the registrant is not required to file reports pursuant
to Section 13 or Section 15(d) of the Act. YES ¨ NO þ

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the
Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90
days. YES þ NO ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive
Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such
files). YES þ NO ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is
not contained herein, and will not be contained, to the best of registrants knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. ¨

Indicate by check mark whether the registrant is a large accelerated filer, an
accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of large accelerated filer, accelerated filer and smaller reporting company in Rule 12b-2 of the Exchange Act. (Check
one):

Large accelerated filer

¨

Accelerated filer þ

Non-accelerated filer

¨ (Do not check if a smaller reporting company)

Smaller reporting company ¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange
Act). YES ¨ NO þ

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant as of June 30, 2015
was approximately $433.3 million, based upon the closing price on the NASDAQ Capital Market reported for such date.

183,074,916 shares held as American Depository Shares (ADS), each representing one Ordinary Share, 50 pence par value per share, and
1,936,818 Ordinary Shares, were outstanding as of February 20, 2016.

DOCUMENTS INCORPORATED BY REFERENCE

Certain information required to be disclosed in Part III of this report is incorporated by reference from the
registrants definitive proxy statement to be filed not later than 120 days after the end of the fiscal year covered by this report.

This Annual Report on Form
10-K contains forward-looking statements. All statements other than statements of historical fact contained in this Annual Report on Form 10-K are forward-looking statements, including statements regarding the progress and timing of our clinical
programs, regulatory filings and commercialization activities, and the potential clinical benefits, safety and market potential of our product candidates, as well as more general statements regarding our expectations for future financial and
operational performance, regulatory environment, and market trends. In some cases, you can identify forward-looking statements by terminology such as may, would, should, could, expects,
aims, plans, anticipates, believes, estimates, predicts, projects, potential, or continue; the negative of these terms; or other comparable
terminology. These statements include but are not limited to statements regarding the commercial success of Vascepa and factors that can affect such success; interpretation of court decisions; expectation on determinations and policy positions of
the United States Food and Drug Administration, or FDA; the expected timing of enrollment, interim results and final results of our REDUCE-IT study; the safety and efficacy of our product and product candidates; expectation regarding the potential
for Vascepa to be partnered, developed and commercialized outside of the United States; expectation on the scope and strength of our intellectual property protection and the likelihood of securing additional patent protection; estimates of the
potential markets for our product candidates; estimates of the capacity of manufacturing and other facilities to support our products; our operating and growth strategies; our industry; our projected cash needs, liquidity and capital resources; and
our expected future revenues, operations and expenditures.

Forward-looking statements are only current predictions and are
subject to known and unknown risks, uncertainties, and other factors that may cause our or our industrys actual results, levels of activity, performance, or achievements to be materially different from those anticipated by such statements.
These factors include, among other things, those listed under Risk Factors in Item 1A of Part I of this Annual Report on Form 10-K and elsewhere in this Annual Report on Form 10-K. These and other factors could cause results to
differ materially from those expressed in these forward-looking statements.

Although we believe that the expectations
reflected in the forward-looking statements contained in this Annual Report on Form 10-K are reasonable, we cannot guarantee future results, performance, or achievements. Except as required by law, we are under no duty to update or revise any of
such forward-looking statements, whether as a result of new information, future events or otherwise, after the date of this Annual Report on Form 10-K.

Unless otherwise indicated, information contained in this Annual Report on Form 10-K concerning our product candidates, the number of patients that may benefit from these product candidates and the
potential commercial opportunity for our product candidates, is based on information from independent industry analysts and third-party sources (including industry publications, surveys, and forecasts), our internal research, and management
estimates. Management estimates are derived from publicly available information released by independent industry analysts and third-party sources, as well as data from our internal research, and based on assumptions made by us based on such data and
our knowledge of such industry, which we believe to be reasonable. None of the sources cited in this Annual Report on Form 10-K has consented to the inclusion of any data from its reports, nor have we sought their consent. Our internal research has
not been verified by any independent source, and we have not independently verified any third-party information. While we believe that such information included in this Annual Report on Form 10-K is generally reliable, such information is inherently
imprecise. In addition, projections, assumptions, and estimates of our future performance are necessarily subject to a high degree of uncertainty and risk due to a variety of factors, including those described in Risk Factors in
Item 1A of Part I of this Annual Report on Form 10-K and elsewhere in this Annual Report on Form 10-K. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by
us.

References in this report to Amarin, the Company, we, our and us refer to
Amarin Corporation plc and its subsidiaries, on a consolidated basis, unless otherwise indicated.

This Annual Report on
Form 10-K includes the registered and unregistered trademarks and service marks of other parties.

Amarin Corporation plc is a
public limited company incorporated under the laws of England and Wales. Amarin Corporation plc was originally incorporated in England as a private limited company on March 1, 1989 under the Companies Act 1985, and re-registered in England as a
public limited company on March 19, 1993. Amarin Corporation plc changed its name from Ethical Holdings plc in 1999.

Our
principal offices are located at 2 Pembroke House, Upper Pembroke Street 28-32, Dublin 2 Ireland. Our registered office is located at One New Change, London EC4M 9AF, England. Our primary office in the United States is located at 1430 Route 206,
Bedminster, NJ 07921, USA. Our telephone number at that location is (908) 719-1315.

For purposes of this Annual Report
on Form 10-K, our ordinary shares may also be referred to as common shares or common stock.

Overview

We are a biopharmaceutical company with expertise in lipid science focused on the commercialization and development of
therapeutics to improve cardiovascular health.

Our lead product, Vascepa® (icosapent ethyl) capsules, is approved by the U.S. Food and Drug Administration, or FDA, for use as an adjunct to
diet to reduce triglyceride levels in adult patients with severe (TG ³500 mg/dL) hypertriglyceridemia. This FDA-approved indication for Vascepa, known as the MARINE indication, is based primarily on the
successful results from the MARINE study of Vascepa in this approved patient population. In considering this approval, FDA also reviewed our successful study of Vascepa in patients with high triglyceride levels (TG
³200 mg/dL and <500 mg/dL) who are also on statin therapy for elevated low-density lipoprotein cholesterol, or LDL-C, levels which condition we refer to as mixed dyslipidemia. This study is known as
the ANCHOR study. Safety data from both the MARINE and ANCHOR studies are reflected in FDA-approved labeling for Vascepa. In January 2013, we began selling and marketing Vascepa in the United States based on the FDA-approved MARINE indication. In
August 2015, we also began marketing Vascepa in the United States for the treatment of patients studied in the ANCHOR study based on the federal court declaration described below. Vascepa is available in the United States by prescription only.

We sell Vascepa principally to a limited number of major wholesalers, as well as selected regional wholesalers and specialty
pharmacy providers, or collectively, its Distributors, that in turn resell Vascepa to retail pharmacies for subsequent resale to patients and healthcare providers. We market Vascepa in the United States through our sales force of approximately 150
sales professionals, including sales representatives and their managers. In March 2014, we entered into a co-promotion agreement in the United States with Kowa Pharmaceuticals America, Inc. under which approximately 250 Kowa Pharmaceuticals America,
Inc. sales representatives began to devote a substantial portion of their time to promoting Vascepa starting in May 2014.

In
February 2015, we announced an exclusive agreement with Eddingpharm (Asia) Macao Commercial Offshore Limited, or Eddingpharm, to develop and commercialize Vascepa capsules in Mainland China, Hong Kong, Macau and Taiwan, or the China Territory. We
are also assessing other partnership opportunities for licensing Vascepa in other territories outside of the United States.

Triglycerides are fats in the blood. Hypertriglyceridemia refers to a condition in which
patients have high levels of triglycerides in the bloodstream. It is estimated that over 70 million adults in the United States have elevated triglyceride levels (TG >150 mg/dL), approximately 40 million adults in the United
States have high triglyceride levels (TG >200 mg/dL), and approximately 4.0 million people in the United States have severely high triglyceride levels (TG >500 mg/dL), commonly known as very high triglyceride levels. Many
patients with high triglyceride levels also have diabetes and other lipid level abnormalities such as high cholesterol. The patient condition of having more than one lipid level abnormality is referred to as mixed dyslipidemia. According to The
American Heart Association Scientific Statement on Triglycerides and Cardiovascular Disease (2011), triglycerides provide important information as a marker associated with the risk for heart disease and stroke, especially when an individual also
has low high-density lipoprotein cholesterol, or HDL-C (often referred to as good cholesterol), and elevated levels of LDL-C (often referred to as bad cholesterol). Guidelines for the management of very high triglyceride
levels suggest that reducing triglyceride levels is the primary goal in patients to reduce the risk of acute pancreatitis. The effect of Vascepa on cardiovascular mortality and morbidity, or the risk for pancreatitis, in patients with
hypertriglyceridemia has not been determined.

We are currently focused on completing the ongoing REDUCE-IT (Reduction of
Cardiovascular Events with EPAIntervention Trial) cardiovascular outcomes study of Vascepa, which we started in December 2011. REDUCE-IT, a multinational, prospective, randomized, double-blind, placebo-controlled study, is the first
prospective cardiovascular outcomes study of any drug in a population of patients who, despite stable statin therapy, have elevated triglyceride levels. Based on the results of REDUCE-IT, we plan to seek additional indicated uses for Vascepa. In
REDUCE-IT, cardiovascular event rates for patients on stable statin therapy plus four grams per day of Vascepa will be compared to cardiovascular event rates for patients on stable statin therapy plus placebo. The REDUCE-IT study is designed to be
completed after reaching 1,612 aggregate cardiovascular events. Based on projected event rates, we estimate the onset of the target aggregate number of cardiovascular events to be reached in or about 2017 with study results then expected to be
available and published in 2018. An interim review of the efficacy and safety results of the trial is scheduled to occur upon reaching 60% of the target aggregate number of cardiovascular events. We currently expect this interim review by the
independent data monitoring committee (DMC) to occur during 2016 and it is our expectation that the trial will run to completion. The DMC has been more frequently examining interim reviews of the safety data from the study. Following each of these
reviews, the DMC has communicated to us that we should continue the study as planned. We remain blinded to all data from the study. Over 99% of the approximately 8,000 patients targeted for enrollment in the REDUCE-IT study have been enrolled and we
have pre-notified all clinical sites in the REDUCE-IT study of our intention to cease patient enrollment soon. Since patient enrollment commenced in 2011, approximately 20,000 patient years of study experience have been accumulated in REDUCE-IT.

In the successful Phase 3 MARINE and ANCHOR clinical trials, Vascepa was studied at a daily dose of 2 grams and 4 grams. We
sought approval of Vascepa at the more efficacious 4-gram dose for use in each patient population. These trials demonstrated favorable results in their respective patient populations, particularly with the 4-gram dose of Vascepa, in reducing
triglyceride levels without increasing LDL-C levels in the MARINE trial and with a statistically significant decrease in LDL-C levels in the ANCHOR trial, in each case, relative to placebo. These trials also showed favorable results, particularly
with the 4-gram dose of Vascepa, in other important lipid and inflammation biomarkers, including apolipoprotein B (apo B), non-high-density lipoprotein cholesterol (non-HDL-C), total-cholesterol (TC), very low-density lipoprotein cholesterol
(VLDL-C), lipoprotein-associated phospholipase A2 (Lp-PLA2), and high sensitivity C-reactive protein (hs-CRP). In these trials, the most commonly reported adverse reaction (incidence >2% and greater than placebo) in Vascepa-treated patients was
arthralgia (joint pain) (2.3% for Vascepa vs. 1.0% for placebo).

In April 2015, we received a Complete Response Letter, or
CRL, from the FDA in response to our supplemental new drug application, or sNDA, that sought approval of Vascepa for use in patients with mixed dyslipidemia, based on the successful ANCHOR study. The CRL followed an October 2013 rescission by the
FDA of a special protocol assessment, or SPA, agreement and three failed attempts by us to appeal that rescission at FDA. The FDA has acknowledged the success of the ANCHOR study, which met all primary and secondary

endpoints. However, FDA determined that there were insufficient data to conclude that drug-induced changes in serum triglycerides could be recognized by the FDA as a valid surrogate for reducing
cardiovascular risk in the ANCHOR population for the purpose of regulatory approval of a drug targeted at a triglyceride-lowering indication in this population. The FDA has acknowledged that the standard of proof required by the FDA for approval of
a new drug indication is higher than that generally used to inform patient treatment guidelines and that used by physicians in clinical practice. The FDA did not determine that the drug-induced effects of Vascepa, which go beyond
triglyceride-lowering, would not actually reduce cardiovascular risk in this population and the FDA has encouraged us to complete the REDUCE-IT outcomes study. Based on our communications with the FDA, we expect that final positive results from the
REDUCE-IT outcomes study will be required for label expansion for Vascepa.

In May 2015, we and a group of independent
physicians filed a lawsuit in federal court to permit us to promote to healthcare professionals the use of Vascepa in patients with mixed dyslipidemia so long as the promotion is truthful and non-misleading. This use reflects recognized medical
practice but is not covered by current FDA-approved labeling for the drug and has thus been considered by FDA to be illegal off-label promotion. In August 2015, we were granted preliminary relief in the form of a declaratory judgment in this
lawsuit. The court declaration permits us to promote to healthcare professionals the FDA-reviewed and agreed effects of Vascepa demonstrated in the ANCHOR clinical trial and presentation of the current state of scientific research related to the
potential of Vascepa to reduce the risk of cardiovascular disease including through use of peer-reviewed scientific publications of available data. The FDA did not appeal the courts ruling prior to the October 6, 2015 deadline. The
underlying litigation has been stayed for settlement discussion and the parties are working toward settlement. In August 2015, we began to promote Vascepa to healthcare professionals as permitted by this court declaration. While we are permitted to
more broadly promote Vascepa based on this court declaration, the FDA-approved labeling for Vascepa did not change based on the court declaration, and neither government nor other third-party coverage or reimbursement to pay for the off-label use of
Vascepa promoted under the court declaration was required.

CommercializationUnited States

We commenced the commercial launch of Vascepa in the United States in January 2013. We commenced sales and shipments of Vascepa at that
time to our network of U.S.-based wholesalers. We now market Vascepa in the United States through our sales force of approximately 150 sales professionals, including sales representatives and their managers. Commencing in May 2014, in addition to
promotion by our sales representatives, approximately 250 Kowa Pharmaceuticals America, Inc. sales representatives began promoting Vascepa. We also employ various marketing personnel to support our commercialization of Vascepa.

Under our co-promotion agreement with Kowa Pharmaceuticals America, Inc., both parties have agreed to use commercially reasonable efforts
to promote, detail and optimize sales of Vascepa in the United States and have agreed to specific performance requirements detailed in the related agreement. The performance requirements include a negotiated minimum number of sales details to be
delivered by each party in the first and second position, the use of a negotiated number of minimum sales representatives from each party, including no less than 250 Kowa Pharmaceuticals America, Inc. sales representatives and the achievement of
minimum levels of Vascepa revenue in 2015 and beyond. First position refers to when a sales representatives primary purpose in detailing is related to Vascepa, while second position refers to when a sales representatives primary purpose
in detailing is to promote another product, but they also devote time in the same sales call to promote Vascepa. Kowa Pharmaceuticals America, Inc. has also agreed to continue to bear the costs incurred for its sales force associated with the
commercialization of Vascepa and to pay for certain incremental costs associated with the use of its sales force, such as sample costs and costs for promotional and marketing materials. We will continue to recognize all revenue from sales of
Vascepa. In exchange for Kowa Pharmaceuticals America, Inc.s co-promotional services, Kowa Pharmaceuticals America, Inc. is entitled to a quarterly co-promotion fee based on a percentage of aggregate Vascepa gross margins that increases during
the term. The percentage of aggregate Vascepa gross margins earned by Kowa Pharmaceuticals America, Inc. increased from the high single digits in

2014, to fifteen percent (15%) in 2015, and is scheduled to increase to the low twenty percent levels in 2018, subject to certain adjustments. The term of this co-promotion agreement expires
on December 31, 2018, following which Kowa Pharmaceuticals America, Inc. will be entitled to earn tail royalties equal to declining fractions of the co-promotion fee in effect prior to such expiration for periods ranging from one to three years
following such expiration.

Based on monthly compilations of data provided by a third party, Symphony Health Solutions, the
estimated number of normalized total Vascepa prescriptions for the three months ended December 31, 2015 was approximately 192,000 compared to 169,000, 148,000, 130,000, and 126,000 in the three months ended September 30,
2015, June 30, 2015, March 31, 2015, and December 31, 2014, respectively. According to data from another third party, IMS Health, the estimated number of normalized total Vascepa prescriptions for the three months ended
December 31, 2015 was approximately 203,000 compared to 176,000, 157,000, 137,000, and 131,000 in the three months ended September 30, 2015, June 30, 2015, March 31, 2015, and December 31, 2014, respectively.
Normalized total prescriptions represent the estimated total number of Vascepa prescriptions shipped to patients, calculated on a normalized basis (i.e., total capsules shipped divided by 120 capsules, or one months supply). The data reported
above is based on information made available to us from third-party resources and may be subject to adjustment and may overstate or understate actual prescriptions. Timing of shipments to wholesalers, as used for revenue recognition purposes, and
timing of prescriptions as estimated by these third parties may differ from period to period. Although we believe these data are prepared on a period-to-period basis in a manner that is generally consistent and that such results are generally
indicative of current prescription trends, these data are based on estimates and should not be relied upon as definitive. While we expect to be able to grow Vascepa revenues over time, no such guidance should be inferred from the operating metrics
described above. We also anticipate that such sales growth may be inconsistent from period to period. We believe that investors should view the above-referenced operating metrics with caution, as data for this limited period may not be
representative of a trend consistent with the results presented or otherwise predictive of future results. Seasonal fluctuations in pharmaceutical sales, for example, may affect future prescription trends of Vascepa, as could changes in prescriber
sentiment and other factors. We believe investors should consider our results over several quarters, or longer, before making an assessment about potential future performance.

The commercialization of pharmaceutical products is a complex undertaking, and our ability to effectively and profitably commercialize Vascepa will depend in part on our ability to generate market demand
for Vascepa through education, marketing and sales activities, our ability to achieve market acceptance of Vascepa, our ability to generate product revenue and our ability to receive adequate levels of reimbursement from third-party payers. See
Risk FactorsRisks Related to the Commercialization and Development of Vascepa.

In August 2015, we
and our co-promotion partner began communicating ANCHOR clinical trial data to targeted healthcare professionals. Such qualified communications are being made pursuant to the August 7, 2015 federal district court declaration allowing truthful
and non-misleading promotion of the FDA-reviewed and agreed effects of Vascepa demonstrated in the ANCHOR clinical trial and presentation of the current state of scientific research related to the potential of Vascepa to reduce the risk of
cardiovascular disease including through use of peer-reviewed scientific publications of available data.

CommercializationOutside the United States

In February 2015, we announced an exclusive agreement with Eddingpharm to develop and commercialize Vascepa capsules in what we refer to as the China Territory, consisting of the territories of Mainland
China, Hong Kong, Macau and Taiwan, for uses that are currently commercialized and under development by us in the United States based on the MARINE, ANCHOR and ongoing REDUCE-IT clinical trials of Vascepa.

Under the agreement, Eddingpharm is responsible for development and commercialization activities in the China Territory and associated
expenses. We will provide development assistance and be responsible for supplying the product. Terms of the agreement include up-front and milestone payments to us of up to $169.0

million, including a non-refundable $15.0 million up-front payment received at closing, and development, regulatory and sales-based milestone payments of up to an additional $154.0 million.
Eddingpharm will also pay us tiered double-digit percentage royalties on net sales of Vascepa in the China Territory escalating to the high teens. We will supply finished product to Eddingpharm under negotiated terms.

We continue to assess other partnership opportunities for licensing Vascepa in other territories outside of the United States.

Research and Development

REDUCE-IT is the first prospective cardiovascular outcomes study of any drug in a population of patients who, despite stable statin therapy, have elevated triglyceride levels. REDUCE-IT is a
multinational, prospective, randomized, double-blind, placebo-controlled study designed to assess the cumulative effect on the rate of cardiovascular events for patients treated with Vascepa as an add-on to statin therapy compared to the
corresponding rate of cardiovascular events for patients treated with placebo on top of statin therapy. Based on the results of REDUCE-IT, we may seek additional indications for Vascepa beyond the indications studied in the ANCHOR or MARINE trials.

REDUCE-IT is designed to enroll approximately 8,000 patients and enrollment is over 99% complete. We have pre-notified all
clinical trial sites in the REDUCE-IT study of our intention to cease further patient enrollment soon. Since patient enrollment commenced in 2011, approximately 20,000 patient years of study experience have been accumulated in REDUCE-IT.

Completion of the REDUCE-IT study is designed to occur after reaching an aggregate number of cardiovascular events. Based on projected
event rates, we estimate the onset of the target aggregate number of cardiovascular events to be reached in or about 2017 with study results then expected to be available in 2018. An interim review of the efficacy and safety results of the trial is
scheduled to occur upon reaching 60% of the target aggregate number of cardiovascular events. We currently expect this interim review by the independent data monitoring committee, or DMC, to occur during 2016. As is typical, the statistical
threshold for defining overwhelming efficacy on the primary endpoint at the interim analysis is considerably higher than the threshold for defining statistical significance at the end of the study and it is our expectation that the trial will run to
completion. In addition, we have instructed the DMC to not recommend stopping the study early based only upon achieving statistical significance for the primary endpoint, but to ensure that statistical significance is also achieved for certain
subpopulations before recommending that the study be stopped early for overwhelming efficacy. Amarin remains blinded to all data from the study. Unless overwhelming efficacy and safety is declared by the DMC at the interim look or the study is
halted due to a patient safety concern, Amarin personnel will remain blinded to the efficacy and safety data from the REDUCE-IT study until the study is complete. The DMC has periodically reviewed unblinded safety data since initiation of the
REDUCE-IT study in 2011 and, after each such meeting to date, has recommended that the study be continued as planned. The pre-specified interim review at 60% of the target aggregate number of cardiovascular events will involve a look by the DMC in
closed session at all efficacy and safety data available from the REDUCE-IT study at that time. Interim looks by independent DMCs are common in large, long-term outcomes studies. By design, it is most common for cardiovascular outcomes studies not
to be stopped upon an interim look.

Our scientific rationale for the REDUCE-IT study is supported by (i) epidemiological
data that suggests elevated triglyceride levels correlate with increased cardiovascular disease risk, (ii) genetic data that suggests triglyceride and/or triglyceride-rich lipoproteins (as well as low-density lipoprotein cholesterol (LDL
cholesterol), known as bad cholesterol) are independently in the causal pathway for cardiovascular disease and (iii) clinical data that suggest substantial triglyceride reduction in patients with elevated baseline triglyceride levels correlates
with reduced cardiovascular risk. Our scientific rationale for the REDUCE-IT study is also supported by research on the putative cardioprotective effects of EPA as presented in scientific literature. It is possible that the effects of EPA may be due
not to a single mode of action, such as triglyceride lowering, but

Prior to 2015, all of our active pharmaceutical ingredient, or API, that has been utilized in product sold was manufactured by two
suppliers: Nisshin Pharma, Inc., or Nisshin, and Chemport, Inc., or Chemport. A significant portion of such API was purchased from Nisshin at a price that is higher than expected future average API costs. During 2015, we began purchasing API from a
third supplier, Finorga SAS, or Novasep. The amount of supply we seek to purchase in future periods will depend on the level of growth of Vascepa revenues and minimum purchase commitments with certain suppliers. We continue efforts to expand,
diversify and enhance our commercial supply chain.

Financial Position

We believe that our cash and cash equivalents balance of $107.0 million as of December 31, 2015 is sufficient to fund our projected
operations for at least the next twelve months. Depending on the level of cash generated from operations, additional capital may be required to sustain operations.

Lipid Disorders and Cardiovascular Disease

Heart attacks, strokes and
other cardiovascular events represent the leading cause of death and disability among men and women in western societies. According to the Heart Disease and Stroke Statistics2016 Update from the American Heart Association, more than 1 out of
every 3 adults in the United States (approximately 86 million) currently lives with one or more types of cardiovascular disease; an estimated 965,000 new or recurrent coronary events and 795,000 new or recurrent strokes occur each year; an estimated
31 million adults ³20 years of age have high total serum cholesterol levels (³240 mg/dL), and an estimated 74 million adults ³20 years of age have borderline high or high low-density lipoprotein (bad) cholesterol, or LDL-C, levels (³130 mg/dL).

In addition to cholesterol, lipoproteins such as LDL also carry fats in the form of triglycerides. Hypertriglyceridemia refers to a
condition in which patients have high levels of triglycerides in the bloodstream and has been recognized as an independent risk factor for cardiovascular disease. Triglyceride levels provide important information as a marker associated with the risk
for heart disease and stroke, especially when an individual also has low high density lipoprotein cholesterol (HDL-C; often called good cholesterol) and elevated levels of LDL-C. The effect of Vascepa on cardiovascular mortality and
morbidity in patients with hypertriglyceridemia has not been determined.

Guidelines for the management of very high
triglyceride levels (³500 mg/dL) suggest that reducing triglyceride levels is the primary treatment goal in these patients to reduce the risk of acute pancreatitis. Treating LDL-C remains an important
secondary goal. Other important parameters to consider in patients with very high triglycerides include levels of apolipoprotein B (apo B), non-HDL-C, very low density lipoprotein cholesterol (VLDL-C), and HDL-C. The effect of Vascepa on the risk
for pancreatitis in patients with hypertriglyceridemia has not been determined.

It is estimated that over 40 million
adults in the United States have elevated triglyceride levels >200 mg/dL and approximately 3 to 4 million people in the United States have very high triglyceride levels (³500 mg/dL). Since
1976, mean triglyceride levels have increased, in concert with the growing epidemic of obesity, insulin resistance, and type 2 diabetes mellitus. In contrast, mean LDL-C levels have decreased.

Mixed dyslipidemia refers to a condition in which patients have a combination of two or more
lipid abnormalities including elevated triglycerides, low HDL-C, and/or elevated LDL-C. Both hypertriglyceridemia and mixed dyslipidemia are components of a range of lipid disorders collectively referred to as dyslipidemia. Dyslipidemia has been
linked to atherosclerosis, commonly referred to as hardening of the arteries.

Limitations of Current Therapies

It is estimated that approximately 4% or less of U.S. adults with triglyceride levels ³200
mg/dL are currently receiving prescription medication for lowering triglycerides. Many of these patients are taking statin therapy directed primarily at lowering their LDL-C levels.

The leading prescription treatments to lower triglyceride levels are fibrates (fenofibrate and gemfibrozil), statins
and generic forms of an omega-3 fatty acid mixture known as Lovaza® in the United States and as Omacor® in Europe. The use of fenofibrates can lead to abnormal liver function tests (an increase in ALT (alanine
transaminase) or AST (aspartate transaminase), which are liver enzymes, and are commonly measured clinically as a part of a diagnostic liver function test to determine liver health), especially when used with statins. The use of gemfibrozil can lead
to rhabdomyolysis (severe breakdown of muscles), especially when used with a statin. Lovaza is comprised of omega-3 ethyl esters, which the FDA has described as a complex mixture of eicosapentaenoic acid, or EPA, docosahexaenoic acid, or DHA, and
other fatty acids. We believe that DHA may increase LDL-C levels and thereby partially offset one of the typically desired benefits of lipid-lowering therapies, which is lowering LDL-C. Also, in 2012, the FDA required an update to Lovaza product
labeling to reflect the risk that Lovaza may increase the frequency of a heart rhythm problem known as atrial fibrillation, or heart flutter. Also, in 2015, the FDA updated the Trilipix® (a fenofibrate) product labeling and removed combination use with statin therapy in mixed dyslipidemia patients as an indication due to a failed outcomes trial.

Potential Benefits and Market Opportunity for Vascepa

Vascepa is comprised of not less than 96% pure icosapent ethyl, or ethyl-EPA, and contains no DHA. We believe that the removal of DHA mitigates against the LDL-C raising effect observed in omega-3
compositions that include DHA. Based on the results of the MARINE trial, Vascepa was the first omega-3 based product to demonstrate statistically significant triglyceride reduction without a statistically significant increase in LDL-C in this very
high triglyceride population.

We believe that the results of the MARINE trial and Vascepas EPA only/DHA-free
composition suggest that Vascepa has the potential to become a best-in-class triglyceride-lowering agent in the United States and the European Union. If the REDUCE-IT cardiovascular outcomes study is successful, Vascepa could be the
first omega-3 based therapy approved for lowering high triglycerides in patients with mixed dyslipidemia and for prevention of cardiovascular events as an add-on to statin therapy in this population.

We believe the potential market for Vascepa is large and growing. We estimate that drug treatment for hypercholesterolemia patients
exceeds $66 billion per year in the United States, with sales dominated by statin therapies. U.S. sales of fibrates as a class of products were approximately $3.7 billion in 2015 with generic fenofibrate and gemfibrozil leading the class. U.S. gross
sales of prescription omega-3 therapies in 2015 were over $1.4 billion with generic Lovaza leading the class.

Clinical Trials

The MARINE Trial (basis for currently FDA-approved label for Vascepa)

The MARINE trial, the largest study ever conducted with the omega-3 fatty acid ethyl EPA in treating patients with very high triglycerides
(³500 mg/dL), was a Phase 3, multi-center, placebo-controlled, randomized, double-blind, 12-week study. Patients were randomized into three treatment arms for treatment with Vascepa 4 gram/day, 2 gram/day
or placebo. Patient enrollment in this trial began in December 2009, and enrollment and

randomization was completed in August 2010 at 229 patients. The primary endpoint in the trial was the percentage change in triglyceride level from baseline compared to placebo after 12 weeks of
treatment. The MARINE study primary endpoint was required to meet a stringent level of statistical significance of 1% (p < 0.01) in our Special Protocol Assessment, or SPA, agreement with the FDA.

In November 2010, we reported top-line data for the MARINE trial. In the trial, Vascepa met its primary endpoint at doses of 4 grams and
2 grams per day with median placebo-adjusted reductions in triglyceride levels of 33% (p < 0.0001) compared to placebo for 4 grams and 20% (p = 0.0051) compared to placebo for 2 grams. The median baseline triglyceride levels were 703 mg/dL, 680
mg/dL and 657 mg/dL for the patient groups treated with placebo, 4 grams of Vascepa and 2 grams of Vascepa, respectively.

In
a pre-specified secondary analysis in the subgroup of patients with baseline triglyceride > 750 mg/dL, representing 39% of all patients, the effect of Vascepa in reducing triglyceride levels compared to placebo was 45% for 4 grams and 33% for 2
grams, both statistically significant (p = 0.0001 for 4 grams and p= 0.0016 for 2 grams, respectively). The median baseline triglyceride levels in this subgroup were 1052 mg/dL, 902 mg/dL and 948 mg/dL for placebo, 4-gram and 2-gram groups,
respectively. Twenty-five percent of patients in this trial were also on background statin therapy. These patients had greater median reduction in triglyceride levels, which was also statistically significant.

Importantly, the significant reduction in triglycerides was not associated with a statistically significant increase in median LDL-C
compared to placebo at either dose (-2.3% for the 4-gram group and +5.2% for the 2-gram group [both p=NS]). In addition, there was a statistically significant decrease in median non-HDL-C (total cholesterol less so-called good
cholesterol) compared to placebo with both of the Vascepa treated groups (-18% for the 4-gram group [p < 0.001] and -8% for the 2-gram group [p < 0.05]).

The MARINE trial results also included statistically significant reductions compared to placebo in several important lipid and inflammatory biomarkers, including apo B (apolipoprotein B) (8.5%), Lp-PLA2
(lipoprotein-phospholipase A2) (13.6%), VLDL-C (very low-density lipoprotein cholesterol) (28.6%), Total Cholesterol (16.3%), and hsCRP (high-sensitivity C-reactive protein) (36.0%) at the 4-gram dose. For these achieved endpoints, p-values
were <0.01 for most and <0.05 for all. Apo B (apolipoprotein B) is believed to be a sensitive biomarker of cardiovascular risk and may be a better predictor of cardiovascular risk than LDL-C. Lp-PLA2 is an enzyme found in blood and
atherosclerotic plaque; high levels have been implicated in the development and progression of atherosclerosis. In a post-hoc analysis of MARINE study data, Vascepa 4 g/day and 2 g/day statistically significantly reduced ApoC-III levels by 25.1% (p
< 0.0001) and 14.3% (p=0.0154) versus placebo, respectively. In the MARINE trial, patients treated with 4 grams per day of Vascepa experienced a significant reduction in median placebo-adjusted lipoprotein particle concentrations of total LDL and
small LDL. When looking at lipoprotein particle concentrations and sizes as measured with nuclear magnetic resonance spectroscopy, Vascepa 4 grams per day, compared with placebo, significantly reduced median total LDL particle count by 16.3%
(p=0.0006), which is an important factor in atherogenesis. LDL particle count and apo B are important risk markers for the prediction of cardiovascular events. Small LDL particle count, which is a common risk factor for cardiovascular events in
patients with diabetes, was reduced by 25.6% (p<0.0001) compared with placebo. Vascepa 2 grams per day, compared with placebo, significantly reduced median small LDL particle count by 12.8% (p <0.05) and reduced median total LDL particle count
by 1.1% (NS). LDL particle size did not change significantly for the 2 or 4 gram per day doses.

Vascepa was well tolerated in
the MARINE trial, with a safety profile comparable to placebo and there were no treatment-related serious adverse events observed. No patient discontinued treatment of Vascepa during this study due to Vascepa-related adverse events. No significant
changes in fasting blood glucose, hemoglobin A1C, vital signs, electrocardiograms, or liver or kidney function were observed with either Vascepa dose.

Patients enrolled in the MARINE trial were given the option to be treated with Vascepa for a period of up to 40 weeks after their last dose in the double-blind portion of the trial. Once participants
completed the randomized, double blind, placebo-controlled 12-week MARINE registration trial, patients in all three

randomized groups (4 grams, 2 grams and placebo) were offered the opportunity to participate in the open label extension, or OLE, phase. Patients in the OLE phase received 4 grams per day of
Vascepa for a period of up to an additional 40 weeks. As is typical of such extension phases, the OLE phase was not a controlled trial, as differentiated from the randomized, double blind, placebo-controlled 12-week MARINE registration trial. In the
OLE phase, participants were not randomized at entry, Vascepa administration was open-label (and thus not blinded), and no placebo group was maintained. Also, once patients entered in the OLE phase, investigators were free to add or modify other
lipid-altering nutritional, lifestyle and drug treatment regimens. Given the lack of randomization, the open-label design, the addition of various other lipid-altering drugs and changes to doses of existing lipid-altering drugs, as well as the lack
of placebo control, neither we nor our independent advisors were able to draw efficacy conclusions from the data. However, we have concluded that the MARINE OLE phase revealed no new safety signals after an additional 40 weeks of exposure to
Vascepa, whether used alone or in combination with other lipid-altering regimens.

The ANCHOR Trial (promoted in the
United States under court declaration)

The ANCHOR trial was a multi-center, placebo-controlled, randomized,
double-blind, 12-week pivotal study in patients with high triglycerides (³200 and <500 mg/dL) who were also receiving optimized statin therapy. Patients were randomized into three arms for treatment
with Vascepa 4 gram/day, 2 gram/day or placebo. Patient enrollment in this trial began in January 2010, and enrollment and randomization was completed in February 2011 at 702 patients. The primary endpoint in the trial was the percentage change in
triglyceride level from baseline compared to placebo after 12 weeks of treatment.

In April 2011, we reported top-line results
from the ANCHOR trial. The ANCHOR trial met its primary endpoint at doses of 4 grams and 2 grams per day with median placebo-adjusted reductions in triglyceride levels of 21.5% (p<0.0001 value) for 4 grams and 10.1% (p=0.0005) for 2 grams. The
median baseline triglyceride levels were 259 mg/dL, 265 mg/dL and 254 mg/dL for the patient groups treated with placebo, 4 grams and 2 grams of Vascepa per day, respectively. The analysis of subgroups by baseline triglyceride tertiles showed that
higher baseline triglycerides resulted in greater triglyceride reductions.

One of the trials secondary endpoints was to
demonstrate a lack of elevation in LDL-C, the primary target of cholesterol lowering therapy. The trials non-inferiority criterion for LDL-C was met at both Vascepa doses. The upper confidence boundaries for both doses were below the
pre-specified +6% LDL-C threshold limit. At the 4-gram dose the upper confidence boundary was below zero (-1.7%) and at the 2-gram dose the upper confidence boundary was close to zero (0.5%). For the 4 grams per day group, LDL-C decreased
significantly by 6.2% from baseline versus placebo, demonstrating superiority over placebo (p=0.0067). For the 2-gram group, LDL-C decreased by 3.6% from baseline versus placebo (p=0.0867), which is not a statistically significant decrease.

Vascepa was well tolerated in the ANCHOR trial with a safety
profile comparable to placebo and there were no treatment-related serious adverse events observed. No significant changes in fasting blood glucose, hemoglobin A1C, vital signs, electrocardiograms, or liver or kidney function were observed with
either Vascepa dose. The safety results from the ANCHOR trial are included in the current FDA-approved label for Vascepa.

In April 2015, we received a Complete Response Letter, or CRL, from the FDA in response to
our supplemental new drug application, or sNDA, that sought approval of Vascepa for use in patients with mixed dyslipidemia, based on the successful ANCHOR study. The CRL followed an October 2013 rescission by the FDA of a special protocol
assessment, or SPA, agreement and three failed attempts by us to appeal that rescission at FDA. The FDA has acknowledged the success of the ANCHOR study, which met all primary and secondary endpoints. However, FDA determined that there were
insufficient data to conclude that drug-induced changes in serum triglycerides could be recognized by the FDA as a valid surrogate for reducing cardiovascular risk in the ANCHOR population for the purpose of regulatory approval of a drug targeted at
a triglyceride-lowering indication in this population. The FDA has acknowledged that the standard of proof required by the FDA for approval of a new drug indication is higher than that generally used to inform patient treatment guidelines and that
used by physicians in clinical practice. The FDA did not determine that the drug-induced effects of Vascepa, which go beyond triglyceride-lowering, would not actually reduce cardiovascular risk in this population and the FDA has encouraged us to
complete the REDUCE-IT outcomes study. Based on our communications with the FDA, we expect that final positive results from the REDUCE-IT outcomes study will be required for label expansion for Vascepa.

In May 2015, we and a group of independent physicians filed a lawsuit in federal court to permit us to promote to healthcare
professionals the use of Vascepa in patients with mixed dyslipidemia so long as the promotion is truthful and non-misleading. This use reflects recognized medical practice but is not covered by current FDA-approved labeling for the drug and has thus
been considered by FDA to be illegal off-label promotion. In August 2015, we were granted preliminary relief in the form of a declaratory judgment in this lawsuit. The court declaration permits us to promote to healthcare professionals the
FDA-reviewed and agreed effects of Vascepa demonstrated in the ANCHOR clinical trial and presentation of the current state of scientific research related to the potential of Vascepa to reduce the risk of cardiovascular disease including through use
of peer-reviewed scientific publications of available data. The FDA did not appeal the courts ruling prior to the October 6, 2015 deadline. The underlying litigation has been stayed for settlement discussion and the parties are working
toward settlement. In August 2015, we began to promote Vascepa to healthcare professionals as permitted by this court declaration. While we are permitted to more broadly promote Vascepa based on this court declaration, the FDA-approved labeling for
Vascepa did not change based on the court declaration, and neither government nor other third-party coverage or reimbursement to pay for the off-label use of Vascepa promoted under the court declaration was required.

Observed Efficacy of Ethyl-EPA

In Japan, ethyl-EPA is marketed under the product name of Epadel by Mochida Pharmaceutical Co. and is indicated for hyperlipidemia and peripheral vascular disease. Clinical data from Japan suggests that
Epadel is effective in reducing triglycerides. In addition, in an outcomes study called the Japan EPA Lipid Intervention Study, or JELIS study, which consisted of more than 18,000 patients followed over multiple years, Epadel, when used in
conjunction with statins, was shown to reduce cardiovascular events by 19% compared to the use of statins alone. In this study, cardiovascular events decreased by approximately 53% compared to statins alone in the subset of primary prevention
patients with triglyceride levels of ³150 mg/dL (median of 272 mg/dL at entry) and HDL-C <40 mg/dL. Epadel has been approved and available by prescription in Japan for over a decade. In 2013, the Japan
Ministry of Health approved Epadel for over-the-counter sales. JELIS provides supportive but not conclusive data that EPA drug therapy may reduce major coronary events. JELIS results cannot be generalized to populations outside of Japan due to
limitations in the studys design. Further study is needed, such as the REDUCE-IT study, to determine the clinical benefit, if any, of EPA therapy in statin-treated patients with elevated triglyceride levels.

Observed Clinical Safety of Vascepa

Prior to commencing the MARINE and ANCHOR trials, we conducted a pre-clinical program for Vascepa, including toxicology and pharmacology studies. In addition, we previously investigated Vascepa in central
nervous system disorders in several double-blind, placebo-controlled studies, including Phase 3 trials in

Huntingtons disease. Over 1,000 patients have been dosed with Vascepa in these studies, with over 100 receiving continuous treatment for a year or more. In all studies performed to date,
Vascepa has shown a favorable safety and tolerability profile. In both the MARINE and ANCHOR trials, patients dosed with Vascepa demonstrated a safety profile similar to placebo. There were no treatment-related serious adverse events in the MARINE
study or in the ANCHOR study. In the MARINE and ANCHOR trials, the most commonly reported adverse reaction (incidence >2% and greater than placebo) in Vascepa treated patients was arthralgia (joint pain) (2.3% for Vascepa vs. 1.0% for placebo).
There was no reported adverse reaction > 3% and greater than placebo.

In addition to the MARINE and ANCHOR trials, we
completed a 28-day pharmacokinetic study in healthy volunteers, a 26-week study to evaluate the toxicity of Vascepa in transgenic mice and multiple pharmacokinetic drug-drug interaction studies in healthy subjects in which we evaluated the effect of
Vascepa on certain common prescription drugs. All findings from these studies were consistent with our expectations and confirmed the overall safety profile of Vascepa.

The REDUCE-IT Study (currently ongoing cardiovascular outcomes study)

In August 2011, we reached agreement with the FDA on an SPA for the design of the REDUCE-IT (Reduction of Cardiovascular Events with
EPAIntervention Trial) cardiovascular outcomes study. In May 2013, we amended the patient enrollment criteria within the SPA agreement with the FDA. An SPA is an evaluation by the FDA of a protocol with the goal of reaching an agreement that
the Phase 3 trial protocol design, clinical endpoints, and statistical analyses are acceptable to support regulatory approval. The FDA agreed that, based on the information we submitted to the agency, the design and planned analysis of the REDUCE-IT
study adequately addressed the objectives necessary to support a regulatory submission. An SPA is generally binding upon the FDA unless a substantial scientific issue essential to determining safety or efficacy of the drug is identified after the
testing begins. Moreover, any change to a study protocol can invalidate an SPA.

In September 2011, we engaged a clinical
research organization, or CRO, and began initial trial and clinical site preparation for REDUCE-IT. In December 2011, we announced that the first patient was dosed in the study. The study duration is dependent on the rate of clinical events in the
study which rate may be affected by the number of patients enrolled in the study, the epidemiology of the patients enrolled in the study, and the length of time that the enrolled patients are followed.

The REDUCE-IT study is designed to evaluate the efficacy of Vascepa in reducing major cardiovascular events in an at-risk patient
population also receiving statin therapy. REDUCE-IT is a multi-center, prospective, randomized, double-blind, placebo-controlled, parallel-group study to evaluate the effectiveness of Vascepa, as an add-on to statin therapy, in reducing first major
cardiovascular events in an at-risk patient population compared to statin therapy alone. The control arm of the study is comprised of patients on optimized statin therapy plus placebo. The active arm of the study is comprised of patients on
optimized statin therapy plus Vascepa. All subjects enrolled in the study will have elevated triglyceride levels and either coronary heart disease or risk factors for coronary heart disease. This study is being conducted internationally.

REDUCE-IT is designed to enroll approximately 8,000 patients and enrollment is over 99% complete. We have pre-notified all clinical trial
sites in the REDUCE-IT study of our intention to cease further patient enrollment soon. Since patient enrollment commenced in 2011, approximately 20,000 patient years of study experience have been accumulated in REDUCE-IT. Completion of the
REDUCE-IT study is designed to occur after reaching an aggregate number of cardiovascular events. Based on projected event rates, we estimate the onset of the target aggregate number of cardiovascular events to be reached in or about 2017 with study
results then expected to be available in 2018. An interim review of the efficacy and safety results of the trial is scheduled to occur upon reaching 60% of the target aggregate number of cardiovascular events. We currently expect this interim review
by the independent data monitoring committee, or DMC, to occur during 2016. As is typical, the statistical threshold for defining overwhelming efficacy on the primary endpoint at the interim analysis is considerably higher than the threshold for
defining statistical significance at the end of the study and it

is our expectation that the trial will run to completion. Amarin remains blinded to all data from the study. Unless overwhelming efficacy and safety is declared by the DMC at the interim look or
the study is halted due to a patient safety concern, Amarin personnel will remain blinded to the efficacy and safety data from the REDUCE-IT study until the study is complete. The DMC has periodically reviewed unblinded safety data since initiation
of the REDUCE-IT study in 2011 and, after each such meeting to date, has recommended that the study be continued as planned. The pre-specified interim review at 60% of the target aggregate number of cardiovascular events will involve a look by the
DMC in closed session at all efficacy and safety data available from the REDUCE-IT study at that time. Interim looks by independent DMCs are common in large, long-term outcomes studies. By design, it is most common for cardiovascular outcomes
studies not to be stopped upon an interim look.

Our scientific rationale for the REDUCE-IT study is supported by
(i) epidemiological data that suggests elevated triglyceride levels correlate with increased cardiovascular disease risk, (ii) genetic data that suggests triglyceride and/or triglyceride-rich lipoproteins (as well as low-density
lipoprotein cholesterol (LDL cholesterol), known as bad cholesterol) are independently in the causal pathway for cardiovascular disease and (iii) clinical data that suggest substantial triglyceride reduction in patients with elevated baseline
triglyceride levels correlates with reduced cardiovascular risk. Our scientific rationale for the REDUCE-IT study is also supported by research on the putative cardioprotective effects of EPA as presented in scientific literature. It is possible
that the effects of EPA may be due not to a single mode of action, such as triglyceride lowering, but rather to multiple mechanisms working together. Studies in the scientific literature explore potentially beneficial effects of EPA on multiple
atherosclerosis processes, including endothelial function, oxidative stress, foam cell formation, inflammation/cytokines, plaque formation/progression, platelet aggregation, thrombus formation, and plaque rupture. The REDUCE-IT study is needed to
determine the clinical benefit, if any, of EPA therapy in statin-treated patients with elevated triglyceride levels.

We
currently expect that final positive results of the REDUCE-IT study will be required for FDA label expansion of Vascepa. Based on the results of REDUCE-IT, we may seek additional indications for Vascepa beyond the indications studied in the ANCHOR
and MARINE trials such as potential indicated uses for prevention of cardiovascular events, although there can be no assurance as to whether the results of the study will support any such indication.

New Lipid Compounds and other Preclinical Programs

We are also considering development of other next generation compounds based on our internal lipid science expertise, including potential combination and derivative therapies.

In August 2013, we completed dosing of AMR102, a fixed dose combination of Vascepa and a leading statin product. The study is a
randomized, open-label, single-dose, 4-way cross-over study to continue testing of the relative bioavailability of AMR102 capsules, Vascepa capsules with the selected statin taken concomitantly, Vascepa taken alone and the selected statin taken
alone. The results of this study support the feasibility of AMR102. We have suspended additional development of AMR102 pending FDA approval of label expansion of Vascepa, anticipated to occur no sooner than after FDA review of the results from the
REDUCE-IT study.

We believe that Vascepa and other lipid-based compositions may have an impact on a number of biological
factors in the body such as anti-inflammatory mechanisms, cell membrane composition and plasticity, triglyceride levels and regulation of glucose metabolism. Currently all other development activities are at formulation or pre-clinical stages.

Manufacturing and Supply for Vascepa

We currently use third-party manufacturers and suppliers to manufacture clinical and commercial quantities of ethyl-EPA, which constitutes the only active pharmaceutical ingredient, or API, within
Vascepa, to encapsulate, bottle and package Vascepa and to maintain inventory of Vascepa. The FDA approval of Vascepa in

July 2012 included the approval of one API manufacturer, Nisshin Pharma, Inc., or Nisshin, and one API encapsulator, Patheon, Inc., or Patheon (formerly Banner Pharmacaps Europe BV). Nisshin and
Patheon are the API manufacturer and API encapsulator, respectively, with which we have had the longest working relationships. Their facilities were approved by the FDA following successful preapproval inspections and they remain active producers of
Vascepa.

We currently rely on Patheon and Capsugel for the encapsulation of Vascepa and we have an encapsulation agreement
with one other qualified commercial API encapsulator.

In addition to purchasing API from Nisshin, we have also purchased API
from Chemport, Inc., or Chemport. In December 2012, we announced our submissions of two sNDAs to the FDA seeking approval for Chemport and BASF (formerly Equateq Limited) as additional Vascepa API suppliers. In April 2013, the FDA approved our sNDAs
covering Chemport and BASF as additional Vascepa API suppliers. On December 30, 2013, we issued a notice of termination of our API agreement to BASF as a result of BASFs non-compliance with the terms of such agreement period and the
agreement subsequently terminated in the first quarter of 2014. BASF remains an approved API supplier. In December 2012, we announced an agreement with an exclusive consortium of companies led by Slanmhor Pharmaceutical, Inc., or Slanmhor. We
submitted a sNDA in August 2013 seeking FDA approval for this supplier to manufacture Vascepa API and in July 2014 the FDA approved our sNDA for Slanmhor as an API supplier. In July 2014, we terminated the supply agreement with Slanmhor and
subsequently, in July 2015, entered into a new supply agreement with Finorga SAS (DBA Novasep), a French company. API manufactured by Finorga (Novasep) was previously approved by the FDA in July 2014.

The API material that constitutes ethyl-EPA is a naturally occurring substance which is sourced from qualified producers of fish oil. A
limited number of other manufacturers have the ability, scale, know-how and suitable facilities to produce ethyl-EPA to a similar level of purity. Among the conditions for FDA approval of a pharmaceutical product is the requirement that the
manufacturers quality control and manufacturing procedures conform to pharmaceutical current Good Manufacturing Practice, or cGMP, which must be followed at all times. The FDA typically inspects manufacturing facilities before regulatory
approval of a product candidate, such as Vascepa, and on a periodic basis after the initial approval. In complying with cGMP regulations, pharmaceutical manufacturers must expend resources and time to ensure compliance with product specifications as
well as production, record keeping, quality control, reporting, and other regulatory requirements.

Some of our agreements
with our API suppliers are exclusive and may include minimum purchase commitments. During 2014 and 2015, we fully met the aggregate minimum purchase requirements for metric tons of API contained in our supply agreements. We may purchase more than
the minimum requirements. Certain of these agreements contemplate phased capacity expansion aimed at creating sufficient capacity to meet anticipated demand for API material for Vascepa. These contracts contain provisions for making lesser payments
to these suppliers in lieu of purchasing the full minimum purchase requirements.

Our Commercialization Plans

In January 2013, we commenced our full commercial launch of Vascepa in the United States for use in the MARINE indication with a direct
sales force of approximately 275 sales representatives. In October 2013, we lowered our number of sales representatives to approximately 130, excluding sales management, in the United States to focus on the sales territories that we believe have
demonstrated the greatest potential for Vascepa sales growth. We now market Vascepa in the United States through our sales force of approximately 150 sales professionals, including sales representatives and their managers. We also employ various
marketing and medical affairs personnel to support our commercialization of Vascepa. We currently target clinicians who are top prescribers of lipid regulating therapies. Commencing in May 2014, in addition to promotion by our sales representatives,
approximately 250 Kowa Pharmaceuticals America, Inc. sales representatives began promoting Vascepa in the United States. We also employ various marketing personnel to support our commercialization of Vascepa.

We are also expanding our commercialization activities to markets outside of the United
States through partnering arrangements. In February 2015, we entered into a commercialization agreement with Eddingpharm (Asia) Macao Commercial Offshore Limited, or Eddingpharm, related to the development and commercialization of Vascepa in
Mainland China, Hong Kong, Macau and Taiwan, or the China Territory. Under this agreement, Eddingpharm is solely responsible for development and commercialization activities in the China Territory and associated expenses. Significant
commercialization of Vascepa in the China Territory is several years away.

We continue to assess other partnership
opportunities for licensing Vascepa in other territories outside of the United States.

Competition

The biotechnology and pharmaceutical industries are highly competitive. There are many pharmaceutical companies, biotechnology companies,
public and private universities and research organizations actively engaged in the research and development of products that may be similar to our products. It is probable that the number of companies seeking to develop products and therapies
similar to our products will increase. Many of these and other existing or potential competitors have substantially greater financial, technical and human resources than we do and may be better equipped to develop, manufacture and market products.
These companies may develop and introduce products and processes competitive with or superior to ours. In addition, other technologies or products may be developed that have an entirely different approach or means of accomplishing the intended
purposes of our products, which might render our technology and products noncompetitive or obsolete.

Our
competitors both in the United States and Europe include large, well-established pharmaceutical companies, specialty pharmaceutical sales and marketing companies, and specialized cardiovascular treatment companies. GlaxoSmithKline plc, which
currently sells Lovaza®, a prescription-only omega-3 fatty acid indicated for patients with severe
hypertriglyceridemia was approved by FDA in 2004 and has been on the market in the United States since 2005. As described below, multiple generic versions of Lovaza are now available in the United States. Other large companies with competitive
products include AbbVie, Inc., which currently sells Tricor® and Trilipix® for the treatment of severe hypertriglyceridemia and mixed dyslipidemia and Niaspan®, which is primarily used to raise HDL-C, but is also used to lower triglycerides. Generic versions of Tricor,
Trilipix, and Niaspan are also now available in the United States. In addition, in May 2014, Epanova®
(omega-3-carboxylic acids) capsules, a free fatty acid form of omega-3 (comprised of 55% EPA and 20% DHA), was approved by the FDA for patients with severe hypertriglyceridemia. Epanova was developed by Omthera Pharmaceuticals, Inc., and is now
owned by AstraZeneca Pharmaceuticals LP (AstraZeneca). Also, in April 2014, Omtryg, another omega-3-acid fatty acid composition developed by Trygg Pharma AS, received FDA approval for severe hypertriglyceridemia. Neither Epanova nor Omtryg have been
commercially launched, but could launch at any time. Each of these competitors, other than potentially Trygg, has greater resources than we do, including financial, product development, marketing, personnel and other resources.

In April 2014, Teva Pharmaceuticals USA Inc., or Teva, launched a generic version of Lovaza after winning its patent litigation against
Pronova BioPharma Norge AS, now owned by BASF, which owns such patents rights. In June 2014 and September 2014, Par Pharmaceutical Inc., or Par, and Apotex Inc., or Apotex, received FDA approval of their respective versions of generic Lovaza. In
March 2011, Pronova/BASF entered into an agreement with Apotex to settle its patent litigation in the United States related to Lovaza. Pursuant to the terms of the settlement agreement, we believe Pronova/BASF granted Apotex a license to enter the
U.S. market with a generic version of Lovaza in the first quarter of 2015, the details of which are not known to us. In the first quarter of 2015, Prasco Labs announced it also has a generic version of Lovaza. Also in 2015, two additional
manufacturers, AvKare Inc., and Amneal Pharmaceuticals, commenced the sale of generic versions of Lovaza.

In addition, we are
aware of other pharmaceutical companies that are developing products that, if approved and marketed, would compete with Vascepa. We understand that Acasti Pharma, a subsidiary of Neptune Technologies & Bioresources Inc., announced in late
2012 that it intends to conduct a Phase 3 clinical program to

assess the safety and efficacy of its omega-3 prescription drug candidate derived from krill oil for the treatment of hypertriglyceridemia. Acasti has not finalized its definitive Phase 3 program
and overall costs and timelines are still contingent upon FDA direction. However, based on their preliminary discussions with FDA, along with Acastis intent to do a pivotal bioavailability bridging study, Acasti believes that a Phase 3 trial
could be initiated in the next 18 months. We believe Catabasis Pharmaceuticals, or Catabasis, Resolvyx Pharmaceuticals, or Resolvyx, and Sancilio & Company are also developing potential treatments for hypertriglyceridemia based on omega-3
fatty acids. To our knowledge, Catabasis initiated a Phase 2 clinical trial of its product in December 2013 which was completed in May 2015 and subsequently deprioritized and placed on hold in June 2015 and Sancilio is preparing to commence Phase 3
clinical testing in 2016. In addition, we are aware that Matinas BioPharma, Inc. is developing an omega-3-based therapeutic for the treatment of severe hypertriglyceridemia and mixed dyslipidemia. Matinas BioPharma, Inc. has filed an Investigational
New Drug Application with the FDA to conduct a human study in the treatment of severe hypertriglyceridemia. Ionis (formerly Isis) Pharmaceuticals and Akcea Therapeutics, its subsidiary announced favorable Phase 2 results of volanesorsen (formerly
called ISIS-APOCIIIRx) a drug candidate administered through
weekly subcutaneous injections, in patients with high triglycerides and type 2 diabetes and in patients with moderate to severe high triglycerides. Finally, Madrigal Pharmaceuticals has completed Phase 1 clinical testing of MGL-3196 for the
treatment of high triglycerides and various lipid parameters in patients.

In addition, we expect that generic drug companies will seek to challenge
the validity and enforceability of our patents and work toward FDA approval for generic versions of Vascepa.

Regulatory Matters

Government Regulation and Regulatory Matters

Any product development activities related to Vascepa or products that we may develop or acquire in the future will be subject to
extensive regulation by various government authorities, including the FDA and comparable regulatory authorities in other countries, which regulate the design, research, clinical and non-clinical development, testing, manufacturing, storage,
distribution, import, export, labeling, advertising and marketing of pharmaceutical products and devices. Generally, before a new drug can be sold, considerable data demonstrating its quality, safety and efficacy must be obtained, organized into a
format specific to each regulatory authority, submitted for review and approved by the regulatory authority. The data is generated in two distinct development stages: pre-clinical and clinical. Drugs must be approved by the FDA through the NDA
process before they are first marketed in the United States. For new chemical entities, the pre-clinical development stage generally involves synthesizing the active component, developing the formulation and determining the manufacturing process, as
well as carrying out non-human toxicology, pharmacology and drug metabolism studies which support subsequent clinical testing.

The clinical stage of development can generally be divided into Phase 1, Phase 2 and Phase 3 clinical trials. In Phase 1, generally, a
small number of healthy volunteers are initially exposed to a single dose and then multiple doses of the product candidate. The primary purpose of these studies is to assess the metabolism, pharmacologic action, side effect tolerability and safety
of the drug. Phase 2 trials typically involve studies in disease-affected patients to determine the dose required to produce the desired benefits. At the same time, safety and further pharmacokinetic and pharmacodynamic information is collected.
Phase 3 trials generally involve large numbers of patients at multiple sites, in multiple countries and are designed to provide the pivotal data necessary to demonstrate the effectiveness of the product for its intended use, its safety in use, and
may include comparisons with placebo and/or other comparator treatments. The duration of treatment is often extended to mimic the actual use of a product during marketing.

In the United States, the process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local,
and foreign statutes and regulations require the expenditure of substantial time and financial resources. Failure to comply with the applicable United States requirements at any time during the product development process, approval process or after
approval, may subject an applicant to administrative or judicial sanctions. These sanctions could include the FDAs refusal to approve pending applications, withdrawal of an approval, a clinical hold, warning letters, product recalls, product
seizures, total or partial suspension of production or distribution injunctions, fines, refusals of government contracts, restitution, disgorgement, or civil or criminal penalties. Any agency or judicial enforcement action could have a material
adverse effect on us.

Prior to the start of human clinical studies for a new drug in the United States, preclinical
laboratory and animal tests are often performed under the FDAs Good Laboratory Practices regulations, or GLP, and an investigational new drug application, or IND, is filed with the FDA. Similar filings are required in other countries; however,
data requirements and other information needed for a complete submission may differ in other countries. The amount of data that must be supplied in the IND depends on the phase of the study. Phase 1 studies typically require less data than larger
Phase 3 studies. A clinical plan must be submitted to the FDA prior to commencement of a clinical trial. If the FDA has concerns about the clinical plan or the safety of the proposed studies, it may suspend or terminate the study at any time.
Studies must be conducted in accordance with good clinical practice and regular reporting of study progress and any adverse experiences is required. Studies are also subject to review by independent institutional review boards, or IRBs, responsible
for overseeing studies at particular sites and protecting human research study subjects. An independent IRB may also suspend or terminate a study once initiated.

NDA and FDA Review Process

Following trial completion, trial data
is analyzed to determine safety and efficacy. Data is then filed with the FDA in an NDA along with proposed labeling for the product and information about the manufacturing and testing processes and facilities that will be used to ensure product
quality. The NDA must contain proof of safety, purity, potency and efficacy, which entails extensive pre-clinical and clinical testing. FDA approval of an NDA must be obtained before first marketing of a drug in the United States.

The FDA will likely re-analyze the clinical trial data, which could result in iterative discussions between the FDA and us during the
review process. The review and evaluation of applications by the FDA is extensive and time consuming and may take longer than originally planned to complete. The FDA may conduct a pre-approval inspection of the manufacturing facilities for the new
product to determine whether they comply with current good manufacturing practice requirements and may also audit data from clinical and pre-clinical trials.

There is no assurance that the FDA will ultimately approve a drug product for marketing in the United States. Even if future indications for Vascepa are approved, the FDAs review will be lengthy and
we may encounter significant difficulties or costs during the review process. After approving any drug product, the FDA may require post-marketing testing and surveillance to monitor the effects of approved products or it may place conditions on
approvals including potential requirements or risk management plans that could restrict the commercial promotion, distribution, prescription or dispensing of products. Product approvals may be withdrawn for non-compliance with regulatory standards
or if problems occur following initial marketing.

Off-label Promotion in the United States

The Federal Food, Drug, and Cosmetic Act, or FDCA, has been interpreted by the FDA to make it illegal for pharmaceutical companies to
promote their products for uses that have not been approved by the FDA. Companies that market drugs for so called off-label uses or indications have been subject to related costly litigation, criminal penalties and civil liability under the False
Claims Act.

In May 2015, we and a group of independent physicians filed a lawsuit against the FDA
seeking a federal court declaration that would permit us and our agents to promote to healthcare professionals the use of Vascepa in patients with mixed dyslipidemia and promote on the potential of Vascepa to reduce the risk of cardiovascular
disease so long as the promotion is truthful and non-misleading. The lawsuit, captioned Amarin Pharma, Inc., et al. v. Food & Drug Administration, et al., S.D.N.Y. (1:15-cv-03588-PAE), was filed in the United States District Court
for the Southern District of New York. In the lawsuit, we contend principally that FDA regulations limiting off-label promotion of truthful and non-misleading information are unconstitutional under the freedom of speech clause of the First Amendment
as applied in the case of our proposed promotion of Vascepa. The physicians in the suit regularly treat patients at risk of cardiovascular disease and, as the complaint contends, have First Amendment rights to receive truthful and non-misleading
information from Amarin. The suit is based on the principle that better informed physicians make better treatment decisions for their patients. This use of Vascepa at issue reflects recognized medical practice but was not approved by the FDA and is
thus not covered by current FDA-approved labeling for the drug. It is therefore considered by the FDA to be illegal off-label promotion. The FDA opposed this lawsuit but did not dispute the veracity of the subject ANCHOR clinical trial data, the
safety data from which is already in FDA-approved labeling of Vascepa, or the peer-reviewed research related to Vascepa and the potential for cardiovascular risk reduction.

In August 2015, we were granted preliminary relief in the form of a declaratory judgment in this lawsuit through the Courts declaratory judgment that confirmed we may engage in truthful and
non-misleading speech promoting the off-label use of Vascepa to healthcare professionals, i.e., to treat patients with persistently high triglycerides, and that such speech may not form the basis of a misbranding action under the Federal Food and
Drug Cosmetic Act. We believe the court declaration permits us to promote to healthcare professionals the FDA-reviewed and agreed effects of Vascepa demonstrated in the ANCHOR clinical trial and presentation of the current state of scientific
research related to the potential of Vascepa to reduce the risk of cardiovascular disease including through use of peer-reviewed scientific publications. We believe this win is in the best interest of patient care because it enables us to more
readily supply accurate information to physicians about Vascepa so they can make informed decisions on how to treat patients based on current, scientific data and consistent with numerous national and international cardiovascular treatment
guidelines and position statements. In August 2015, we began to promote Vascepa to healthcare professionals as permitted by this court declaration. The FDA did not appeal the courts ruling. The underlying litigation has been stayed for
settlement discussion and the parties are working toward settlement. While we are permitted to more broadly promote Vascepa based on this court declaration, the FDA-approved labeling for Vascepa did not change based on the court declaration, and
neither government nor other third-party coverage or reimbursement to pay for the off-label use of Vascepa promoted under the court declaration was required. Based on our communications with the FDA, we expect that final positive results from the
REDUCE-IT outcomes study will be required for label expansion for Vascepa.

Even though we have the benefit of a preliminary
federal court declaration and may be ultimately successful with a final settlement or final ruling in this litigation, our promotion would still be subject to a high, perhaps abnormally high, degree of scrutiny to ensure that our promotion remains
within the scope covered by the declaration. Federal and state governments may also seek to find other means to prevent our promotion of unapproved truthful and non-misleading information about Vascepa. If our operations are found to be in violation
of any of law or governmental regulation through existing or new interpretations, we may be subject to prolonged litigation, penalties, including civil and criminal penalties, damages, fines and the curtailment or restructuring of our operations,
any of which could adversely affect our ability to operate our business and our results of operations.

Foreign
Regulation of New Drug Compounds

In addition to regulations in the United States, we may be subject to a variety of
regulations in other jurisdictions governing, among other things, clinical trials and any commercial sales and distribution of our products.

Whether or not we obtain FDA approval for a product, we must obtain the requisite approvals
from regulatory authorities in all or most foreign countries prior to the commencement of clinical trials or marketing of the product in those countries. Certain countries outside of the United States have a similar process that requires the
submission of a clinical trial application, or CTA, much like the IND prior to the commencement of human clinical trials. In Europe, for example, a CTA must be submitted to each countrys national health authority and an independent ethics
committee, much like the FDA and IRB, respectively. Once the CTA is approved in accordance with a countrys requirements, clinical trial development may proceed. Similarly, all clinical trials in Australia require review and approval of
clinical trial proposals by an ethics committee, which provides a combined ethical and scientific review process.

The
requirements and process governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, the clinical trials must be conducted in accordance with good clinical practices, or GCP,
which have their origin in the World Medical Associations Declaration of Helsinki, the applicable regulatory requirements, and guidelines developed by the International Conference on Harmonization, or ICH, for GCP practices in clinical trials.

Post-Marketing Requirements

Following approval of a new product, a pharmaceutical company generally must engage in numerous specific monitoring and recordkeeping activities and continue to submit periodic and other reports to the
applicable regulatory agencies, including any cases of adverse events and appropriate quality control records. Modifications or enhancements to the products or labeling or changes of site of manufacture are often subject to the approval of the FDA
and other regulators, which may or may not be received or may result in a lengthy review process.

Prescription drug
advertising is subject to federal, state and foreign regulations. In the United States, the FDA regulates prescription drug promotion, including direct-to-consumer advertising. Prescription drug promotional materials must be submitted to the FDA in
conjunction with their first use. Any distribution of prescription drug products and pharmaceutical samples must comply with the U.S. Prescription Drug Marketing Act, or the PDMA, a part of the FDCA.

In the United States, once a product is approved, its manufacture is subject to comprehensive and continuing regulation by the FDA. The
FDA regulations require that products be manufactured in specific approved facilities and in accordance with pharmaceutical current good manufacturing practices, or cGMPs, and NDA holders must list their products and register their manufacturing
establishments with the FDA. These regulations also impose certain organizational, procedural and documentation requirements with respect to manufacturing and quality assurance activities. NDA holders using contract manufacturers, laboratories or
packagers are responsible for the selection and monitoring of qualified firms, and, in certain circumstances, qualified suppliers to these firms. These firms and, where applicable, their suppliers are subject to inspections by the FDA at any time,
and the discovery of violative conditions, including failure to conform to cGMPs, could result in enforcement actions that interrupt the operation of any such facilities or the ability to distribute products manufactured, processed or tested by
them.

Federal and State Fraud and Abuse Laws

In addition to FDA restrictions on marketing of pharmaceutical products, several other types of state and federal laws restrict certain
marketing practices in the biopharmaceutical industry. These laws include anti-kickback statutes and false claims statutes.

The federal anti-kickback statute prohibits, among other things, knowingly and willfully offering, paying, soliciting, or receiving
remuneration to induce or in return for a referral or the purchasing, leasing, ordering, or arranging for or recommending the purchase, lease, or order of any healthcare facility, item or service reimbursable under Medicare, Medicaid, or other
federal healthcare programs. This statute has been interpreted

to apply to arrangements between pharmaceutical manufacturers on one hand and prescribers, purchasers, and formulary managers on the other. Although there are a number of statutory exemptions and
regulatory safe harbors protecting certain activities from prosecution, the exemptions and safe harbors are drawn narrowly, and practices that involve remuneration intended to induce prescribing, purchases, or recommendations may be subject to
scrutiny if they do not qualify for an exemption or safe harbor. Our practices may not in all cases meet all of the criteria for safe harbor protection from anti-kickback liability.

Federal false claims laws prohibit any person from knowingly presenting, or causing to be presented, a false claim for payment to the
federal government, or knowingly making or using, or causing to be made or used, a false statement to get a false claim paid. Recently, several pharmaceutical and other healthcare companies have been prosecuted under these laws for allegedly
providing free product to customers with the expectation that the customers would bill federal programs for the product. Other companies have been prosecuted for causing false claims to be submitted because of the companys marketing of the
product for unapproved, and thus non-reimbursable, uses. The majority of states also have statutes or regulations similar to the federal anti-kickback law and false claims laws, which apply to items and services reimbursed under Medicaid and other
state programs, or, in several states, apply regardless of the payer. Sanctions under these federal and state laws may include civil monetary penalties, exclusion of a manufacturers products from reimbursement under government programs,
criminal fines, and imprisonment.

Because of the breadth of these laws and the narrowness of the safe harbors, it is possible
that some of our business activities could be subject to challenge under one or more of such laws. Such a challenge could have a material adverse effect on our business, financial condition and results of operations. As a company marketing an
FDA-approved product in the United States, our operations may be directly, or indirectly through our customers, subject to various federal and state fraud and abuse laws, including, without limitation, the federal anti-kickback statute. These laws
may impact, among other things, our proposed sales, marketing and education programs. In addition, we may be subject to patient privacy regulation by both the federal government and the states in which we conduct our business. The laws that may
affect our ability to operate include:



the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which created new federal criminal statutes that prohibit executing
a scheme to defraud any healthcare benefit program and making false statements relating to healthcare matters;



HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and its implementing regulations, which imposes
certain requirements relating to the privacy, security and transmission of individually identifiable health information; and



state law equivalents of each of the above federal laws, such as anti-kickback and false claims laws which may apply to items or services reimbursed by
any third-party payer, including commercial insurers, and state laws governing the privacy and security of health information in certain circumstances, many of which differ from each other in significant ways and may not have the same effect, thus
complicating compliance efforts.

If our operations are found to be in violation of any of the laws
described above or any other governmental regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines and the curtailment or restructuring of our operations, any of which could adversely
affect our ability to operate our business and our results of operations.

In the United States and foreign jurisdictions,
there have been a number of legislative and regulatory changes to the healthcare system that could affect our future results of operations. In particular, there have been and continue to be a number of initiatives at the United States federal and
state levels that seek to reduce healthcare costs. The Medicare Prescription Drug, Improvement, and Modernization Act of 2003, or the MMA, imposed new requirements for the distribution and pricing of prescription drugs for Medicare beneficiaries.
Under Part D, Medicare beneficiaries may enroll in prescription drug plans offered by private entities which will provide coverage of outpatient prescription drugs. Part D plans include both stand-alone prescription drug benefit

plans and prescription drug coverage as a supplement to Medicare Advantage plans. Unlike Medicare Part A and B, Part D coverage is not standardized. Part D prescription drug plan sponsors are not
required to pay for all covered Part D drugs, and each drug plan can develop its own drug formulary that identifies which drugs it will cover and at what tier or level. However, Part D prescription drug formularies must include drugs within each
therapeutic category and class of covered Part D drugs, though not necessarily all the drugs in each category or class. Any formulary used by a Part D prescription drug plan must be developed and reviewed by a pharmacy and therapeutic committee.
Government payment for some of the costs of prescription drugs may increase demand for our products for which we receive marketing approval. However, any negotiated prices for our products covered by a Part D prescription drug plan will likely be
lower than the prices we might otherwise obtain. Moreover, while the MMA applies only to drug benefits for Medicare beneficiaries, private payers often follow Medicare coverage policy and payment limitations in setting their own payment rates. Any
reduction in payment that results from the MMA may result in a similar reduction in payments from non-governmental payers.

The American Recovery and Reinvestment Act of 2009 provides funding for the federal government to compare the effectiveness of different
treatments for the same illness. A plan for the research will be developed by the Department of Health and Human Services, the Agency for Healthcare Research and Quality and the National Institutes for Health, and periodic reports on the status of
the research and related expenditures will be made to Congress. Although the results of the comparative effectiveness studies are not intended to mandate coverage policies for public or private payers, it is not clear what effect, if any, the
research will have on the sales of any product, if any such product or the condition that it is intended to treat is the subject of a study. It is also possible that comparative effectiveness research demonstrating benefits in a competitors
product could adversely affect the sales of our product candidates. If third-party payers do not consider our products to be cost-effective compared to other available therapies, they may not cover our products as a benefit under their plans or, if
they do, the level of payment may not be sufficient to allow us to sell our products on a profitable basis.

In March 2010 the
Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, or collectively the PPACA, was enacted, which includes measures to significantly change the way healthcare is financed by both governmental
and private insurers. Among the provisions of the PPACA of greatest importance to the pharmaceutical and biotechnology industry are the following:



an annual, nondeductible fee on any entity that manufactures or imports certain branded prescription drugs and biologic products, apportioned among
these entities according to their market share in certain government healthcare programs, that began in 2011;



new requirements to report certain financial arrangements with physicians and others, including reporting any transfer of value made or
distributed to prescribers and other healthcare providers and reporting any investment interests held by physicians and their immediate family members;



a licensure framework for follow-on biologic products;



a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical effectiveness research, along
with funding for such research;



creation of the Independent Payment Advisory Board which, beginning in 2014, will have authority to recommend certain changes to the Medicare program
that could result in reduced payments for prescription drugs and those recommendations could have the effect of law even if Congress does not act on the recommendations; and



establishment of a Center for Medicare and Medicaid Innovation at the Centers for Medicare & Medicaid Services to test innovative payment and
service delivery models to lower Medicare and Medicaid spending, potentially including prescription drug spending that began on January 1, 2011.

Other Regulatory Matters

Manufacturing, sales, promotion, and other
activities following product approval are also subject to regulation by numerous regulatory authorities in addition to the FDA, including, in the United States, the Centers for Medicare & Medicaid Services, other divisions of the Department
of Health and Human Services, the Drug

Enforcement Administration, the Consumer Product Safety Commission, the Federal Trade Commission, the Occupational Safety & Health Administration, the Environmental Protection Agency,
and state and local governments. Sales, marketing and scientific/educational programs must also comply with the U.S. Medicare-Medicaid Anti-Fraud and Abuse Act and similar state laws. Pricing and rebate programs must comply with the Medicaid rebate
requirements of the U.S. Omnibus Budget Reconciliation Act of 1990. If products are made available to authorized users of the Federal Supply Schedule of the General Services Administration, additional laws and requirements apply. The handling of any
controlled substances must comply with the U.S. Controlled Substances Act and Controlled Substances Import and Export Act. Products must meet applicable child-resistant packaging requirements under the U.S. Poison Prevention Packaging Act.
Manufacturing, sales, promotion and other activities are also potentially subject to federal and state consumer protection and unfair competition laws.

The distribution of pharmaceutical products is subject to additional requirements and regulations, including extensive record-keeping, licensing, storage and security requirements intended to prevent the
unauthorized sale of pharmaceutical products.

The failure to comply with regulatory requirements subjects firms to possible
legal or regulatory action. Depending on the circumstances, failure to meet applicable regulatory requirements can result in criminal prosecution, fines or other penalties, injunctions, recall or seizure of products, total or partial suspension of
production, denial or withdrawal of product approvals, or refusal to allow a firm to enter into supply contracts, including government contracts. In addition, even if a firm complies with FDA and other requirements, new information regarding the
safety or effectiveness of a product could lead the FDA to modify or withdraw a product approval. Prohibitions or restrictions on sales or withdrawal of future products marketed by us could materially affect our business in an adverse way.

Changes in regulations or statutes or the interpretation of existing regulations could impact our business in the future by
requiring, for example: (i) changes to our manufacturing arrangements; (ii) additions or modifications to product labeling; (iii) the recall or discontinuation of our products; or (iv) additional record-keeping requirements. If
any such changes were to be imposed, they could adversely affect the operation of our business.

FDA Marketing
Exclusivity

The FDCA, as amended by the Drug Price Competition and Patent Term Restoration Act of 1984, as amended, or
the Hatch-Waxman Amendments, provides for market exclusivity provisions that can help protect the exclusivity of new drugs by delaying the acceptance and final approval of certain competitive drug applications. NCE marketing exclusivity precludes
final approval during the five-year exclusivity period of certain 505(b)(2) applications and abbreviated new drug applications, or ANDAs, submitted by another company for another version of the drug. However, an application may be submitted after
four years if it contains a certification of patent invalidity or non-infringement. In this case, Amarin, as a pioneer drug company, may be afforded the benefit of a 30-month stay against the launch of such a competitive product that would extend
from the end of the five-year exclusivity period, and could also be afforded other extensions under applicable regulations, including a six-month pediatric exclusivity extension or a judicial extension if applicable requirements are met. Another
drug sponsor could also gain a form of marketing exclusivity under the provisions of the Hatch-Waxman Amendments, if such company can, under certain circumstances, complete a human clinical trial process and obtain regulatory approval of its
product. Additional three-year periods of exclusivity can be obtained for studies resulting in approval for new uses of existing drugs that protect the pioneer drug company from approval of ANDA applications made with reference to the new use during
the three years from approval.

The FDA typically makes a determination on marketing exclusivity in connection with an
approval of an application for a new indication of a drug. We applied to the FDA for five-year, NCE marketing exclusivity for Vascepa in connection with the NDA for our MARINE indication, which NDA was approved by the FDA on July 26, 2012 as
the first FDA approval of Vascepa.

On February 21, 2014, in connection with the July 26, 2012 approval of the MARINE
indication, the FDA denied a grant of NCE marketing exclusivity to Vascepa and granted three-year marketing exclusivity.

On
February 27, 2014, we sued the FDA in the U.S. District Court for the District of Columbia to challenge the agencys denial of five-year NCE exclusivity for Vascepa, based on our reading of the relevant statute, our view of FDAs
inconsistency with its past actions in this area and the retroactive effect of what we believe is a new policy at FDA as it relates to our situation.

On May 28, 2015, the Court granted our motion for summary judgment. This lawsuit sought an order requiring FDA to recognize five-year, NCE marketing exclusivity for Vascepa. The decision vacated the
FDAs denial of our claim for such exclusivity and remanded to the FDA for proceedings consistent with the decision. FDA did not appeal the Courts decision prior to the July 28, 2015 deadline for appeal. A new exclusivity
determination by FDA has not been made.

On July 22, 2015, Watson Laboratories Inc., the purported first Vascepa ANDA
filer, sought to intervene and appeal the Courts decision. We and FDA opposed this intervention effort. The applicable courts denied Watson the relief sought and appeal periods have expired.

Based on the May 28, 2015 District of Columbia court order granting our motion for summary judgment in the NCE litigation, on
June 26, 2015, the parties to the related Vascepa patent litigation that followed acceptance by FDA of ANDAs to Vascepa agreed to a full stay of proceeding in that patent litigation.

Following the May 28, 2015 District of Columbia court order setting aside FDAs denial of NCE exclusivity for Vascepa, FDA
notified the ANDA filers that FDA had changed the status of their ANDAs to submitted, but no longer accepted. Therefore, the statutory basis for the patent litigation (accepted ANDAs) no longer existed. Thus, on July 24, 2015, we moved to
dismiss the pending patent infringement lawsuits against each of the Vascepa ANDA applicants in the U.S. District Court for the District of New Jersey.

On January 22, 2016, the U.S. District Court for the District of New Jersey granted Amarins motion to dismiss all patent infringement litigation related to the acceptance by the FDA of ANDAs to
Vascepa, which were originally filed in the first half of 2014. With this dismissal, there is no pending patent litigation related to Vascepa. A notice of appeal of the courts dismissal was filed by one ANDA filer in this case and we intend to
continue to litigate vigorously in support of the courts dismissal. We cannot predict the outcome of this litigation.

We plan to defend the exclusivity of Vascepa through patent litigation after notification that FDA has accepted an ANDA application
related to Vascepa. Assuming an NCE exclusivity determination from the FDA or no exclusivity determination, we expect notification of new ANDA submissions no sooner than in late July 2016, after the expiration of four years from the 2012 approval of
Vascepa.

FDA marketing exclusivity is separate from, and in addition to, patent protection, trade secrets and manufacturing
barriers to entry which also help protect Vascepa against generic competition.

Patents, Proprietary Technology, Trade Secrets

Our success depends in part on our ability to obtain and maintain intellectual property protection for our drug
candidates, technology and know-how, and to operate without infringing the proprietary rights of others. Our ability to successfully implement our business plan and to protect our products with our intellectual property will depend in large part on
our ability to:



obtain, defend and maintain patent protection and market exclusivity for our current and future products;



preserve any trade secrets relating to our current and future products;

Amarin has prosecuted, and is currently prosecuting, multiple patent applications to protect
the intellectual property developed during the Vascepa cardiovascular program. As of the date of this report, we had 46 patent applications in the United States that have been either issued or allowed and more than 30 additional patent applications
are pending in the United States. Such 46 allowed and issued applications include the following:



2 issued U.S. patents directed to a pharmaceutical composition of Vascepa in a capsule that have terms that expire in 2020 and 2030, respectively,

36 U.S. patents covering the use of Vascepa in either the MARINE or anticipated ANCHOR indication that have terms that expire in 2030,



3 additional patents related to the use of a pharmaceutical composition comprised of free fatty acids to treat the ANCHOR patient population with a
term that expires in 2030,



2 additional patents related to the use of a pharmaceutical composition comprised of free fatty acids to treat the MARINE patient population with a
term that expires in 2030,



1 additional patent related to a pharmaceutical composition comprised of free fatty acids and uses thereof to treat both the MARINE and ANCHOR patient
populations with a term that expires in 2030, and



1 additional patent related to a formulation of EPA/DHA and uses thereof with a term that expires in 2030.

A Notice of Allowance is issued after the USPTO makes a determination that a patent can be granted from an application. A Notice of
Allowance does not afford patent protection until the underlying patent is issued by the USPTO. No assurance can be given that applications with issued notices of allowance will be issued as patents or that any of our pending patent applications
will issue as patents. No assurance can be given that, if and when issued, our patents will prevent competitors from competing with Vascepa. We are also pursuing patent applications related to Vascepa in multiple jurisdictions outside the United
States. We may be dependent in some cases upon third-party licensors to pursue filing, prosecution and maintenance of patent rights or applications owned or controlled by those parties. It is possible that third parties will obtain patents or other
proprietary rights that might be necessary or useful to us. In cases where third parties are first to invent a particular product or technology, or first to file after various provisions of the America Invents Act of 2011 went into effect on
March 16, 2013, it is possible that those parties will obtain patents that will be sufficiently broad so as to prevent us from utilizing such technology or commercializing our current and future products.

Although we intend to make reasonable efforts to protect our current and future intellectual property rights and to ensure that any
proprietary technology we acquire or develop does not infringe the rights of other parties, we may not be able to ascertain the existence of all potentially conflicting claims. Therefore, there is a risk that third parties may make claims of
infringement against our current or future products or technologies. In addition, third parties may be able to obtain patents that prevent the sale of our current or future products or require us to obtain a license and pay significant fees or
royalties in order to continue selling such products.

We may in the future discover the existence of products that infringe
patents that we own or that have been licensed to us. If we were to initiate legal proceedings against a third party to stop such an infringement, such proceedings could be costly and time consuming, regardless of the outcome. No assurances can be
given that we would prevail, and it is possible that, during such a proceeding, our patent rights could be held to be invalid, unenforceable or both. Although we intend to protect our trade secrets and proprietary know-how through confidentiality
agreements with our manufacturers, employees and consultants, we may not be able to prevent parties subject to such confidentiality agreements from breaching these agreements or third parties from independently developing or learning of our trade
secrets.

We anticipate that competitors may from time to time oppose our efforts to obtain patent
protection for new technologies or to submit patented technologies for regulatory approvals. Competitors may seek to oppose our patent applications to delay the approval process or to challenge our granted patents, for example, by requesting a
reexamination of our patent at the USPTO, or by filing an opposition in a foreign patent office, even if the opposition or challenge has little or no merit. Such proceedings are generally highly technical, expensive, and time consuming, and there
can be no assurance that such a challenge would not result in the narrowing or complete revocation of any patent of ours that was so challenged.

Employees

At February 20, 2016, we had 210 full-time employees
employed in sales, marketing, general and administrative and research and development functions. We believe our relations with our employees are good.

Organizational Structure

At February 20, 2016, we had the following
subsidiaries:

Subsidiary Name

Country ofIncorporationor Registration

Proportion ofOwnership
Interest andVoting Power Held

Amarin Pharmaceuticals Ireland Limited

Ireland

100

%

Amarin Pharma Inc.

United States

100

%

Amarin Neuroscience Limited

Scotland

100

%

Corsicanto Ltd

Ireland

100

%

Ester Neurosciences Limited

Israel

100

%

Our principal offices are located at 2 Pembroke House, Upper Pembroke Street 28-32, Dublin 2 Ireland. Our
registered office is located at One New Change, London EC4M 9AF, England. Our primary offices in the United States are located at 1430 Route 206, Bedminster, NJ 07921, USA. Our telephone number at that location is (908) 719-1315. Our website
address is www.amarincorp.com. No information contained on, or accessible through, our website is incorporated by reference into this Annual Report on Form 10-K.

As of the date of this Annual Report on Form 10-K, our principal operating activities were being conducted by Amarin Corporation plc, together with Amarin Pharmaceuticals Ireland Limited and Amarin
Pharma, Inc., with little to no operating activity being conducted by Amarin Neuroscience Limited, Corsicanto Ltd, or Ester Neurosciences Limited.

On January 9, 2012, Amarin, through its wholly-owned subsidiary Corsicanto Limited, a private limited company incorporated under the laws of Ireland, completed a private placement of $150.0 million
in aggregate principal amount of its 3.5% exchangeable senior notes due 2032, a portion of which were exchanged in May 2014 (the 2014 Notes) and a portion of which were extinguished in 2015 and replaced with new 3.5% exchangeable senior notes due
2032 (the 2015 Notes). The 2012 and 2014 Notes are the senior unsecured obligations of Corsicanto and are guaranteed by Amarin Corporation plc. The 2015 Notes are the senior unsecured obligations of Amarin Corporation plc and are not guaranteed by
any entity. Corsicanto was formed in November 2011 and was subsequently acquired by Amarin in January 2012 for the sole purpose of facilitating this financing transaction.

Financial Information

The financial information required under this
Item 1 is incorporated herein by reference to Item 8 of this Annual Report on Form 10-K.

You are advised to read this Annual Report on Form 10-K in conjunction with other reports and documents that we file from time to time
with the Securities and Exchange Commission, or SEC. You may obtain copies of these reports after the date of this annual report directly from us or from the SEC at the SECs Public Reference Room at 100 F Street, N.E. Washington, D.C. 20549.
In addition, the SEC maintains information for electronic filers (including Amarin) at its website at www.sec.gov. The public may obtain information regarding the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. We make
our periodic and current reports, as well as any amendments to such reports, available on our internet website, free of charge, as soon as reasonably practicable after such material is electronically filed with, or furnished to, the SEC.

Item 1A.

Risk Factors

This Annual Report on Form 10-K contains forward-looking information based on our current expectations. Because our actual results may differ materially from any forward-looking statements that we make
or that are made on our behalf, this section includes a discussion of important factors that could affect our actual future results, including, but not limited to, our ability to successfully commercialize Vascepa, our capital resources, the
progress and timing of our clinical programs, the safety and efficacy of our product candidates, risks associated with regulatory filings, the potential clinical benefits and market potential of our product candidates, commercial market estimates,
future development efforts, patent protection, effects of healthcare reform, reliance on third parties, and other risks set forth below.

Risks Related to the Commercialization and Development of Vascepa

We are substantially dependent upon sales of Vascepa in the United States.

As a result of our reliance on a single product, Vascepa (icosapent ethyl) capsules, and our primary focus on the U.S. market in the near-term, much of our near-term results and value as a company depends
on our ability to execute our commercial strategy for Vascepa in the United States. If commercialization efforts for Vascepa are not successful, our business will be materially and adversely affected.

Even if we are able to develop Vascepa outside the United States or develop additional products from our research and development
efforts, the development time cycle for products typically takes several years. This restricts our ability to respond to adverse business conditions for Vascepa. If we are not successful with development, or if there is not adequate demand for
Vascepa or the market for such product develops less rapidly than we anticipate, we may not have the ability to effectively shift our resources to the development of alternative products or do so in a timely manner without suffering material adverse
effects on our business. As a result, the lack of alternative markets and products we develop could constrain our ability to generate revenues and achieve profitability.

The uncertain effect of Vascepa on its ultimate targeted clinical benefit makes it more difficult to achieve a level of market acceptance by physicians, patients, healthcare payors and others in the
medical community necessary for commercial success.

In January 2013, we launched Vascepa based on FDA approval of our
MARINE indication, for use as an adjunct to diet to reduce triglyceride levels in adult patients with severe (TG ³500 mg/dL) hypertriglyceridemia. Approximately 4.0 million people in the United
States have severely high triglyceride levels (TG >500 mg/dL), commonly known as very high triglyceride levels. Guidelines for the management of very high triglyceride levels suggest that reducing triglyceride levels is the primary goal in
patients to reduce the risk of acute pancreatitis. A secondary goal for this patient population is to reduce cardiovascular risk. The effect of Vascepa on cardiovascular mortality and morbidity, or the risk for pancreatitis, in patients with
hypertriglyceridemia has not been determined and our FDA-approved labeling and promotional efforts state these facts.

In August 2015, based on a federal court order, we also began marketing Vascepa in the
United States to healthcare professionals for the treatment of patients with high (TG ³200 mg/dL and <500 mg/dL) triglyceride levels who are also on statin therapy for elevated low-density lipoprotein
cholesterol, or LDL-C, levels, based on results from the ANCHOR study of Vascepa. It is estimated that approximately 40 million adults in the United States have high triglyceride levels (TG >200 mg/dL), and many patients with high
triglycerides also have other lipid level abnormalities such as high cholesterol and are on statin therapy. FDA did not approve Vascepa for use in this population due to the uncertain effect of pharmaceutically induced triglyceride reduction in this
patient population on cardiovascular risk reduction, the ultimate targeted clinical benefit. Our promotional efforts disclose this fact and what we view as truthful and non-misleading information on the current state of research on both triglyceride
reduction and the active pharmaceutical ingredient in Vascepa, EPA, as each relate to the potential of Vascepa to reduce cardiovascular risk.

The uncertainties around the ultimate clinical benefit of Vascepa make it more difficult for Vascepa to gain market acceptance by physicians, patients, healthcare payors and others in the medical
community. If Vascepa does not achieve an adequate level of acceptance, we may not generate significant product revenues and we may not become profitable. The degree of market acceptance of Vascepa for the MARINE indication and in ANCHOR patients
and any future approved indications will depend on a number of factors, including:



the perceived efficacy, safety and potential advantages of Vascepa, as compared to alternative treatments;



our ability to offer Vascepa for sale at competitive prices;



convenience and ease of administration compared to alternative treatments;



the willingness of the target patient population to try new therapies and of physicians to prescribe these therapies;



the scope, effectiveness and strength of product education, marketing and distribution support, including our sales and marketing team;



publicity concerning Vascepa or competing products;



the ultimate outcome or settlement terms of our pending litigation to expand our ability to promote Vascepa in the United States outside of
FDA-approved labeling and the related perception thereof;



sufficient third-party coverage or reimbursement for on-label use, and for permitted off-label use the third-party coverage or reimbursement for which
was not addressed in the scope of the August 2015 court declaration; and



the actual efficacy of the product and the prevalence and severity of any side effects, including any limitations or warnings contained in
Vascepas approved labeling.

Our current and planned commercialization efforts may not be
successful in increasing sales of Vascepa.

In January 2013, we began selling and marketing Vascepa in the United
States through our own, newly established sales and marketing teams and through a newly established third-party commercial distribution infrastructure. We hired key personnel in these areas over the last several years and hired and trained a
professional sales force in early January 2013. In October 2013, following an FDA advisory committee recommendation against approval for the ANCHOR indication, we implemented a plan to reduce our workforce and our team of sales professionals in
half.

In May 2014 we began co-promoting Vascepa in the United States with Kowa Pharmaceuticals America, Inc. under a
co-promotion agreement we entered into in March 2014. Under the agreement, approximately 250 Kowa Pharmaceuticals America, Inc. sales representatives devote a substantial portion of their time to promoting

Vascepa with Amarins approximately 130 sales representatives based on a plan designed to increase both the number of sales targets reached and the frequency of sales calls on existing sales
targets. However, the commercialization of pharmaceutical products is a complex undertaking for a company to manage, and we have very limited experience as a company operating in this area and co-promoting a pharmaceutical product with a partner.

We are also expanding our commercialization activities to markets outside of the United States through partnering
arrangements. On February 26, 2015, we entered into a Development, Commercialization and Supply Agreement (the DCS Agreement) with Eddingpharm (Asia) Macao Commercial Offshore Limited (Eddingpharm) related to the
development and commercialization of Vascepa in Mainland China, Hong Kong, Macau and Taiwan, or the China Territory. Under the DCS Agreement, Eddingpharm will be solely responsible for development and commercialization activities in the China
Territory and associated expenses. Additionally, Eddingpharm may be required to conduct clinical trials in the China Territory to secure regulatory approval. Significant commercialization of Vascepa in the China Territory is several years away. If
Eddingpharm is not able to effectively develop and commercialize Vascepa in the China Territory, we may not be able to generate revenue from the DCS Agreement resulting from the sale of Vascepa in the China Territory.

We have limited experience working with ex-U.S. partners such as Eddingpharm to develop and market our products in foreign countries. In
order for Eddingpharm, or us, to market and sell Vascepa in any country outside of the United States for any indication, it will be necessary to obtain regulatory approval from the appropriate regulatory authorities. The requirements and timing for
regulatory approval, which may include conducting clinical trials, vary widely from country to country and may in some cases be different than or more rigorous than requirements in the United States. Any failure by us or Eddingpharm to obtain
approval for Vascepa in any countries outside of the United States in a timely manner may limit the commercial success of Vascepa and our ability to grow our revenues.

Factors related to building and managing a sales and marketing organization that can inhibit our efforts to successfully commercialize Vascepa include:

our inability to adequately train our sales and marketing personnel, in particular as it relates to various healthcare regulatory requirements
applicable to the marketing and sale of pharmaceutical products and the court declaration that we believe enables us to expand marketing efforts for Vascepa, and our inability to adequately monitor compliance with these requirements;



the inability of our new sales personnel, working for us as a new market entrant, to obtain access to or persuade adequate numbers of physicians to
prescribe Vascepa;



the lack of complementary products to be offered by sales personnel, which may put us at a competitive disadvantage relative to companies with more
extensive product lines;



an inability by us or our partners to obtain regulatory and marketing approval or establish marketing channels in foreign jurisdictions; and



unforeseen costs and expenses associated with operating a new independent sales and marketing organization.

If we are not successful in our efforts to market and sell Vascepa, our anticipated revenues will be materially and negatively affected,
and we may not obtain profitability, may need to cut back on research and development activities or need to raise additional funding that could result in substantial dilution.

We expect final positive results from the REDUCE-IT outcomes study will be required for FDA-approved label expansion for Vascepa.

Since January 2013 we have marketed Vascepa for use in the FDA-approved MARINE indication in the United States.

In April 2015, we received a CRL from the FDA on our Supplemental New Drug Application
(sNDA) that sought approval for the use of Vascepa in patients with high triglyceride levels (TG ³200 mg/dL and <500 mg/dL) who are also on statin therapy, which we refer to as the ANCHOR
indication. In regulatory dialogue, the FDA acknowledged that the results of the ANCHOR trial as we presented them to FDA were valid and truthful in that, for example, Vascepa reduced triglyceride levels compared to placebo in patients treated in
the ANCHOR study. The clinical rationale for reducing serum triglycerides with Vascepa and modifying other lipid/lipoprotein parameters shown in ANCHOR among statin-treated patients with triglycerides 200-499 mg/dL is to reduce cardiovascular risk.
In not approving our ANCHOR sNDA, the FDA concluded that, for regulatory approval purposes, there are insufficient data at this time to support a drug-induced change in serum triglycerides as a surrogate for reducing cardiovascular risk in the
ANCHOR population. The FDA did not determine that the drug-induced effects of Vascepa, which go beyond triglyceride-lowering, would not actually reduce cardiovascular risk in this population.

In August 2015, based on a federal court order, we began marketing Vascepa in the United States to healthcare professionals for the
treatment of patients in the ANCHOR population through use of a set of qualified statements that reflect the current state of research related to this use. An FDA-approved indication for this patient population was not granted. Our ability to reach
full potential in the commercialization of Vascepa in the United States is dependent upon marketing claims associated with Vascepa that are granted with the approval of an indication statement by the FDA.

Based on our communications with the FDA, we expect that final positive results from the REDUCE-IT outcomes study will be required for
FDA approval of a new indication or other label expansion for Vascepa. Any delay in obtaining, or an inability to obtain, further expansion of our marketing approval rights with an FDA approval could prevent us from growing revenue at greater than
our current pace and could therefore have a material adverse effect on our operations and financial condition, including our ability to reach profitability. Even if we obtain additional regulatory approvals for Vascepa, the timing or scope of any
approvals may prohibit or reduce our ability to commercialize the product successfully. For example, if the approval process for any expanded indication takes too long, we may miss market opportunities and give other companies the ability to develop
competing products or establish market dominance. If the FDA does not approve any expanded indication at all, it could have a material impact on our future results of operations and financial condition. Additionally, the terms of any approvals
beyond the approval received from the FDA in July 2012 for the MARINE indication may prove to not have the scope or breadth needed for us to successfully commercialize Vascepa or become profitable.

Our off-label promotion of Vascepa could subject us to additional regulatory scrutiny and present unforeseen risks.

The Federal Food, Drug, and Cosmetic Act, or FDCA, has been interpreted by the FDA to make it illegal for
pharmaceutical companies to promote their products for uses that have not been approved by the FDA. Companies that market drugs for so called off-label uses or indications have been subject to related costly litigation, criminal penalties and civil
liability under the False Claims Act.

In May 2015, we and a group of independent physicians filed a lawsuit against the FDA
seeking a federal court declaration that would permit us and our agents to promote to healthcare professionals the use of Vascepa in patients with mixed dyslipidemia and promote on the potential of Vascepa to reduce the risk of cardiovascular
disease so long as the promotion is truthful and non-misleading. This use of Vascepa at issue reflects recognized medical practice but was not approved by the FDA and is thus not covered by current FDA-approved labeling for the drug. It is therefore
considered by the FDA to be illegal off-label promotion. The lawsuit, captioned Amarin Pharma, Inc., et al. v. Food & Drug Administration, et al., S.D.N.Y. (1:15-cv-03588-PAE), was filed in the United States District Court for the
Southern District of New York. In the lawsuit, we contend principally that FDA regulations limiting off-label promotion of truthful and non-misleading information are unconstitutional under the freedom of speech clause of the First Amendment as
applied in the case of our proposed promotion of

Vascepa. The physicians in the suit regularly treat patients at risk of cardiovascular disease and, as the complaint contends, have First Amendment rights to receive truthful and non-misleading
information from Amarin. The suit is based on the principle that better informed physicians make better treatment decisions for their patients. The FDA opposed this lawsuit but did not dispute the veracity of the subject ANCHOR clinical trial data,
the safety data from which is already in FDA-approved labeling of Vascepa, or the peer-reviewed research related to Vascepa and the potential for cardiovascular risk reduction.

In connection with this litigation, the FDA sent a detailed letter to us on June 5, 2015 that confirmed the validity of the ANCHOR
trial results. The letter also sought to clarify how, in the FDAs view, applicable law and FDA policies apply to the communications proposed in Amarins complaint. FDA stated in this letter that it did not have concerns with much of the
information Amarin proposed to communicate and provided Amarin with guidance on the FDAs view of lawful, but limited paths for the dissemination and communication to healthcare professionals of the effects of Vascepa demonstrated in the ANCHOR
clinical trial and use of peer-reviewed scientific publications in the context of appropriate disclaimers. The litigation continued after receipt of this letter because significant issues remained despite the significant steps forward provided by
the June 5 letter. Such issues included, but were not limited to, the ability of Amarin to engage in a full and truthful dialogue with healthcare professionals about the success of the ANCHOR trial and the potential effectiveness of Vascepa as
a treatment to reduce cardiovascular risk.

In August 2015, we were granted preliminary relief in the form of a declaratory
judgment in this lawsuit through the Courts declaratory judgment that confirmed we may engage in truthful and non-misleading speech promoting the off-label use of Vascepa to healthcare professionals, i.e., to treat patients with persistently
high triglycerides, and that such speech may not form the basis of a misbranding action under the Federal Food and Drug Cosmetic Act. We believe the court declaration permits us to promote to healthcare professionals the FDA-reviewed and agreed
effects of Vascepa demonstrated in the ANCHOR clinical trial and presentation of the current state of scientific research related to the potential of Vascepa to reduce the risk of cardiovascular disease including through use of peer-reviewed
scientific publications. We believe this win is in the best interest of patient care because it enables us to more readily supply accurate information to physicians about Vascepa so they can make informed decisions on how to treat patients based on
current, scientific data and consistent with numerous national and international cardiovascular treatment guidelines and position statements. In August 2015, we began to promote Vascepa to healthcare professionals as permitted by this court
declaration. The FDA did not appeal the courts ruling. The underlying litigation has been stayed for settlement discussion and the parties are working toward settlement. We cannot predict the outcome of settlement negotiations or this
litigation. The legal process can be unpredictable, costly and time-consuming and even if we are successful the remedies available to us may be less beneficial to us than we currently believe.

While we are permitted to more broadly promote Vascepa based on this court declaration, the FDA-approved labeling for Vascepa did not
change based on the court declaration, and neither government nor other third-party coverage or reimbursement to pay for the off-label use of Vascepa promoted under the court declaration was required. Based on our communications with the FDA, we
expect that final positive results from the REDUCE-IT outcomes study will be required for label expansion for Vascepa.

Even
though we have the benefit of a preliminary federal court declaration and may be ultimately successful with a final settlement or final ruling in this litigation, our promotion would still be subject to a high, perhaps abnormally high, degree of
scrutiny to ensure that our promotion remains within the scope covered by the declaration. Federal and state governments may also seek to find other means to prevent our promotion of unapproved truthful and non-misleading information about Vascepa.
If our operations are found to be in violation of any law or governmental regulation through existing or new interpretations, we may be subject to prolonged litigation, penalties, including civil and criminal penalties, damages, fines and the
curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations.

We may not be able to compete effectively against our competitors pharmaceutical
products.

The biotechnology and pharmaceutical industries are highly competitive. There are many pharmaceutical
companies, biotechnology companies, public and private universities and research organizations actively engaged in the research and development of products that may be similar to our products. It is probable that the number of companies seeking to
develop products and therapies similar to our products will increase. Many of these and other existing or potential competitors have substantially greater financial, technical and human resources than we do and may be better equipped to develop,
manufacture and market products. These companies may develop and introduce products and processes competitive with or superior to ours. In addition, other technologies or products may be developed that have an entirely different approach or means of
accomplishing the intended purposes of our products, which might render our technology and products noncompetitive or obsolete.

Our competitors both in the United States and Europe include large, well-established pharmaceutical companies, specialty pharmaceutical sales and marketing companies, and specialized cardiovascular
treatment companies. GlaxoSmithKline plc, which currently sells Lovaza®, a prescription-only omega-3 fatty acid
indicated for patients with severe hypertriglyceridemia was approved by FDA in 2004 and has been on the market in the United States since 2005. As described below, multiple generic versions of Lovaza are now available in the United States. Other
large companies with competitive products include AbbVie, Inc., which currently sells Tricor® and Trilipix® for the treatment of severe hypertriglyceridemia and mixed dyslipidemia and Niaspan®, which is primarily used to raise HDL-C, but is also used to lower triglycerides. Generic versions of Tricor,
Trilipix, and Niaspan are also now available in the United States. In addition, in May 2014, Epanova®
(omega-3-carboxylic acids) capsules, a free fatty acid form of omega-3 (comprised of 55% EPA and 20% DHA), was approved by the FDA for patients with severe hypertriglyceridemia. Epanova was developed by Omthera Pharmaceuticals, Inc., and is now
owned by AstraZeneca Pharmaceuticals LP (AstraZeneca). Also, in April 2014, Omtryg, another omega-3-acid fatty acid composition developed by Trygg Pharma AS, received FDA approval for severe hypertriglyceridemia. Neither Epanova nor Omtryg have been
commercially launched, but could launch at any time. Each of these competitors, other than potentially Trygg, has greater resources than we do, including financial, product development, marketing, personnel and other resources.

In April 2014, Teva Pharmaceuticals USA Inc., or Teva, launched a generic version of Lovaza after winning its patent litigation against
Pronova BioPharma Norge AS, now owned by BASF, which owns such patents rights. In June 2014 and September 2014, Par Pharmaceutical Inc., or Par, and Apotex Inc., or Apotex, received FDA approval of their respective versions of generic Lovaza. In
March 2011, Pronova/BASF entered into an agreement with Apotex to settle its patent litigation in the United States related to Lovaza. Pursuant to the terms of the settlement agreement, we believe Pronova/BASF granted Apotex a license to enter the
U.S. market with a generic version of Lovaza in the first quarter of 2015, the details of which are not known to us. In the first quarter of 2015, Prasco Labs announced it also has a generic version of Lovaza.

In addition, we are aware of other pharmaceutical companies that are developing products that, if approved and
marketed, would compete with Vascepa. We understand that Acasti Pharma, a subsidiary of Neptune Technologies & Bioresources Inc., announced in late 2012 that it intends to conduct a Phase 3 clinical program to assess the safety and efficacy
of its omega-3 prescription drug candidate derived from krill oil for the treatment of hypertriglyceridemia. We believe Catabasis Pharmaceuticals, or Catabasis, Resolvyx Pharmaceuticals, or Resolvyx, and Sancilio & Company are also
developing potential treatments for hypertriglyceridemia based on omega-3 fatty acids. To our knowledge, Catabasis initiated a Phase 2 clinical trial of its product in December 2013; Resolvyxs compound remains in Phase 1 clinical testing; and
Sancilio is preparing to commence Phase 3 clinical testing. In addition, we are aware that Matinas BioPharma, Inc. is developing an omega-3-based therapeutic for the treatment of severe hypertriglyceridemia and mixed dyslipidemia. Matinas BioPharma,
Inc. has filed an Investigational New Drug Application with the FDA to conduct a human study in the treatment of severe hypertriglyceridemia. Isis Pharmaceuticals announced favorable Phase 2 results of ISIS-APOCIIIRx a drug candidate administered through weekly subcutaneous injections,
in patients with high triglycerides and type 2

diabetes and in patients with moderate to severe high triglycerides. Finally, Madrigal Pharmaceuticals has completed Phase 1 clinical testing of MGL-3196 for the treatment of high triglycerides
and various lipid parameters in patients.

The regulatory exclusivity status of Vascepa remains uncertain creating
uncertainty around to what degree we will continue to enjoy the benefits we have to date in the absence of a definitive five-year regulatory exclusivity determination for Vascepa.

The timelines and conditions under the abbreviated new drug application (ANDA) process that permit the start of patent
litigation and allow the FDA to approve generic versions of brand name drugs like Vascepa differ based on whether a drug receives three-year, or five-year, new chemical entity (NCE) marketing exclusivity. The FDA typically makes a determination on
marketing exclusivity in connection with an NDA approval of a drug for a new indication. We applied to the FDA for five-year, NCE marketing exclusivity for Vascepa in connection with the NDA for our MARINE indication, which NDA was approved by the
FDA on July 26, 2012. On February 21, 2014, in connection with the July 26, 2012 approval of the MARINE indication, the FDA denied a grant of NCE marketing exclusivity to Vascepa and granted three-year marketing exclusivity. Under
applicable regulations, such three-year exclusivity would have extended through July 25, 2015 and would have been supplemented by a 30-month stay triggered by patent litigation that would have extended into September 2016, unless such patent
litigation was resolved against us sooner.

NCE marketing exclusivity, not granted to Vascepa at this time, precludes approval
during the five-year exclusivity period of certain 505(b)(2) applications and ANDAs submitted by another company for another version of the drug. However, an application may be submitted after four years if it contains a certification of patent
invalidity or non-infringement. In this case, the pioneer drug company may be afforded the benefit of a 30-month stay against the launch of such a competitive product that would extend from the end of the five-year exclusivity period, and may also
be afforded other extensions under applicable regulations, including a six-month pediatric exclusivity extension or a judicial extension if applicable requirements are met. Another drug sponsor could also gain a form of marketing exclusivity under
the provisions of the FDCA, as amended by the Hatch-Waxman Amendments, if such company can, under certain circumstances, complete a human clinical trial process and obtain regulatory approval of its product.

The three-year period of exclusivity granted to Vascepa under the Hatch-Waxman Amendments is for a drug product that contains an active
moiety that has been previously approved when the application contains reports of new clinical investigations (other than bioavailability studies) conducted by the sponsor that were essential to approval of the application. Accordingly, we expect to
receive three-year exclusivity in connection with any future regulatory approvals of Vascepa, such as an approval sought based on positive REDUCE-IT outcomes study results.

Such three-year exclusivity protection precludes the FDA from approving a marketing application for an ANDA, a product candidate that the FDA views as having the same conditions of approval as Vascepa
(for example, the same indication and/or other conditions of use), or a 505(b)(2) NDA submitted to the FDA with Vascepa as the reference product, for a period of three years from the date of FDA approval. The FDA may accept and commence review of
such applications during the three-year exclusivity period. Such three-year exclusivity grant does not prevent a company from challenging the validity of patents at any time, subject to any prior four-year period pending from a grant of five-year
exclusivity. This three-year form of exclusivity may also not prevent the FDA from approving an NDA that relies only on its own data to support the change or innovation.

As noted above, the FDA typically makes a determination on marketing exclusivity in connection with an approval of an application for a new indication of a drug. We applied to the FDA for five-year, NCE
marketing exclusivity for Vascepa in connection with the NDA for our MARINE indication, which NDA was approved by the FDA on July 26, 2012 as the first FDA approval of Vascepa. On February 21, 2014, in connection with the

July 26, 2012 approval of the MARINE indication, the FDA denied a grant of NCE marketing exclusivity to Vascepa and granted three-year marketing exclusivity.

On February 27, 2014, we sued the FDA in the U.S. District Court for the District of Columbia to challenge the agencys denial
of five-year NCE exclusivity for Vascepa, based on our reading of the relevant statute, our view of FDAs inconsistency with its past actions in this area and the retroactive effect of what we believe is a new policy at FDA as it relates to our
situation.

On May 28, 2015, the Court granted our motion for summary judgment. This lawsuit sought an order requiring
FDA to recognize five-year, NCE marketing exclusivity for Vascepa. The decision vacated the FDAs denial of our claim for such exclusivity and remanded to the FDA for proceedings consistent with the decision. FDA did not appeal the Courts
decision prior to the July 28, 2015 deadline for appeal. A new exclusivity determination by FDA has not been made.

On
July 22, 2015, Watson Laboratories Inc., the purported first Vascepa ANDA filer, sought to intervene and appeal the Courts decision. We and FDA opposed this intervention effort. The applicable courts denied Watson the relief sought and
appeal periods have expired.

A new exclusivity determination by FDA has been pending since the May 28, 2015 District of
Columbia court order setting aside FDAs denial of NCE exclusivity for Vascepa. We believe Vascepa is entitled to NCE exclusivity, but cannot predict the outcome of FDAs determination. It is possible that FDAs determination would be
challenged by interested parties.

Recent regulatory determinations and court decisions have provided us with certain benefits
of five-year regulatory exclusivity in the United States, such as delayed generic-related patent litigation and cessation of ANDA review at FDA. However, the uncertain status of our regulatory exclusivity at the FDA has, and is expected to continue
to have, a negative impact on our company as we have not been able to obtain certainty on an exclusivity grant and thereby certainty around the benefits associated with a definitive five-year exclusivity status. Additional delays at FDA in making an
exclusivity decision, a denial of NCE exclusivity for Vascepa, additional associated litigation and uncertainty surrounding our regulatory exclusivity status generally could continue to have a negative effect on our company.

FDA marketing exclusivity is separate from, and in addition to, patent protection, trade secrets and manufacturing barriers to entry
which also help protect Vascepa against generic competition.

Generic company competitors are expected to again seek
approval of generic versions of Vascepa.

The Food Drug and Cosmetic Act, or FDCA, as amended by the Drug Price
Competition and Patent Term Restoration Act of 1984, as amended, or the Hatch-Waxman Amendments, permit the FDA to approve ANDAs for generic versions of brand name drugs like Vascepa. We refer to the process of generic drug applications as the
ANDA process. The ANDA process permits competitor companies to obtain marketing approval for a drug product with the same active ingredient, dosage form, strength, route of administration, and labeling as the approved brand name drug,
but without having to conduct and submit clinical studies to establish the safety and efficacy of the proposed generic product. In place of such clinical studies, an ANDA applicant needs to submit data demonstrating that its product is bioequivalent
to the brand name product, usually based on pharmacokinetic studies.

The Hatch-Waxman Amendments require an applicant for a
drug product that relies, in whole or in part, on the FDAs prior approval of Vascepa, to notify us of its application, a paragraph IV notice, if the applicant is seeking to market its product prior to the expiration of the patents that claim
Vascepa. A bona fide paragraph IV notice may not be given under the Hatch-Waxman Amendments until after the generic company receives from the FDA an acknowledgement letter stating that its ANDA is sufficiently complete to permit a substantive
review.

The paragraph IV notice is required to contain a detailed factual and legal statement
explaining the basis for the applicants opinion that the proposed product does not infringe our patents, that our patents are invalid, or both. After receipt of a valid notice, we would have the option of bringing a patent infringement suit in
federal district court against any generic company seeking approval for its product within 45 days from the date of receipt of each notice. If such a suit is commenced within this 45 day period, we will be entitled to receive a 30 month stay on
FDAs ability to give final approval to any of the proposed products that reference Vascepa that begins on the date we receive the paragraph IV notice. The stay may be shortened or lengthened if either party fails to cooperate in the litigation
and it may be terminated if the court decides the case in less than 30 months. If the litigation is resolved in favor of the applicant before the expiration of the 30 month period, the stay will be immediately lifted and the FDAs review of the
application may be completed. Such litigation is often time-consuming and costly, and may result in generic competition if such patents are not upheld or if the generic competitor is found not to infringe such patents.

In the first half of 2014, we received six paragraph IV notices notifying us of accepted ANDAs to Vascepa under the Hatch-Waxman
Amendments. These ANDAs were submitted and accepted by FDA under the regulatory scheme adopted under the Hatch-Waxman Amendments based on the FDAs determination that we were entitled to three, and not five-year exclusivity. As a result from
the first half of 2014 until June 2015, we were engaged in costly litigation with the ANDA applicants to protect our patent rights.

Based on the May 28, 2015, District of Columbia court order granting our motion for summary judgment in the NCE litigation, on June 26, 2015, the parties to the related Vascepa patent litigation
that followed acceptance by FDA of ANDAs to Vascepa based on a three-year regulatory exclusivity determination, agreed to a full stay of proceeding in that patent litigation.

Following the May 28, 2015 District of Columbia court order setting aside FDAs denial of NCE exclusivity for Vascepa, FDA notified the ANDA filers that FDA had changed the status of their ANDAs
to submitted, but no longer accepted, and notified ANDA filers that FDA had ceased review of the pending ANDAs. In rescinding acceptance of the ANDAs, the statutory basis for the patent litigation (accepted ANDAs) no longer existed. Thus, on
July 24, 2015, we moved to dismiss the pending patent infringement lawsuits against each of the Vascepa ANDA applicants in the U.S. District Court for the District of New Jersey.

On January 22, 2016, the U.S. District Court for the District of New Jersey granted Amarins motion to dismiss all patent
infringement litigation related to the 2014 acceptance by the FDA of ANDAs to Vascepa. With this dismissal, there is no pending patent litigation related to Vascepa. A notice of appeal of the courts dismissal was filed by one ANDA filer in
this case and we intend to continue to litigate vigorously in support of the courts dismissal. We cannot predict the outcome of this litigation. A new exclusivity determination by FDA has been pending since the May 28, 2015 District of
Columbia court order setting aside FDAs denial of NCE exclusivity for Vascepa. We believe Vascepa is entitled to NCE exclusivity, but cannot predict the outcome of FDAs determination. We also cannot predict the outcome of this ANDA
litigation. The legal process can also be costly and time-consuming.

We plan to defend the exclusivity of Vascepa through
patent litigation after notification that FDA has accepted an ANDA application related to Vascepa. Assuming an NCE exclusivity determination from the FDA or no exclusivity determination, we expect notification of new ANDA submissions no sooner than
in late July 2016, after the expiration of four years from the 2012 approval of Vascepa.

If an ANDA filer is ultimately
successful in patent litigation against us, it meets the requirements for a generic version of Vascepa to the satisfaction of the FDA under its ANDA (after any applicable regulatory exclusivity period and the litigation-related 30-month stay period
expires), and is able to supply the product in significant commercial quantities, the generic company could introduce a generic version of Vascepa. Such a market entry would likely limit our U.S. sales, which would have an adverse impact on our
business and results of operations. In addition, even if a competitors effort to introduce a generic product is ultimately unsuccessful, the perception that such development is in progress and/or news related to such progress could materially
affect the perceived value of our company and our stock price.

Vascepa is a prescription-only omega-3 fatty acid product. Omega-3 fatty acids are
also marketed by other companies as non-prescription dietary supplements. As a result, Vascepa is subject to non-prescription competition and consumer substitution.

Our only current product, Vascepa, is a prescription-only omega-3 fatty acid. Mixtures of omega-3 fatty acids are naturally occurring substances contained in various foods, including fatty fish. Omega-3
fatty acids are also marketed by others as non-prescription dietary supplements. We cannot be sure physicians will view the pharmaceutical grade purity and tested safety of Vascepa as having a superior therapeutic profile to naturally occurring
omega-3 fatty acids and dietary supplements. In addition, the FDA has not enforced what we view as illegal drug claims made by certain supplement manufacturers to the extent we believe appropriate under applicable law and regulations, for example,
claims that such supplements reduce triglyceride levels. Also, for more than a decade now, the FDA has expressly permitted dietary supplement manufacturers that sell supplements containing the omega-3 fatty acids EPA and/or DHA to make the following
qualified health claim directly to consumers: Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease. Under the preliminary ruling in our First Amendment
litigation, we may now make this claim to healthcare professionals subject to certain qualifications. These factors enable dietary supplements to effectively compete with Vascepa. In addition, to the extent the net price of Vascepa after insurance
and offered discounts is significantly higher than the prices of commercially available omega-3 fatty acids marketed by other companies as dietary supplements (through that lack of coverage by insurers or otherwise), physicians and pharmacists may
recommend these commercial alternatives instead of writing or filling prescriptions for Vascepa or patients may elect on their own to take commercially available omega-3 fatty acids. Either of these outcomes may adversely impact our results of
operations by limiting how we price our product and limiting the revenue we receive from the sale of Vascepa due to reduced market acceptance.

We may not be successful in our Vascepa co-promotion effort with Kowa Pharmaceuticals America, Inc.

In March 2014, we entered into a co-promotion agreement with Kowa Pharmaceuticals America, Inc. to co-promote Vascepa in the United States under which approximately 250 Kowa Pharmaceuticals America, Inc.
sales representatives devote a substantial portion of their time to promoting Vascepa with Amarins approximately 130 sales representatives. Co-promotion under the agreement commenced in May 2014 based on a plan designed to substantially
increase both the number of sales targets reached and the frequency of sales calls on existing sales targets. While our agreement provides for minimum performance criteria, we have little control over Kowa Pharmaceuticals America, Inc., and it may
fail to devote the necessary resources and attention to promote Vascepa effectively. If that were to occur, depending on Vascepa revenues, we may have to curtail the continued development of Vascepa for approval for additional indications or
increase our planned expenditures and undertake additional development or commercialization activities at our own expense. Or, we may seek to terminate the agreement and search for another commercialization partner. If we elect to increase our
expenditures to fund development or commercialization activities on our own, depending on Vascepas revenues, we may need to obtain additional capital, which may not be available to us on acceptable terms, or at all, or which may not be
possible due to our other financing arrangements. If we do not generate sufficient funds from the sale of Vascepa or, to the extent needed to supplement funds generated from product revenue, cannot raise sufficient funds, we may not be able to
devote resources sufficient to market and sell Vascepa on our own in a manner required to realize the full market potential of Vascepa.

The commercial value to us of current and sought marketing rights may be smaller than we anticipate.

There can be no assurance as to the adequacy for commercial success of the scope and breadth of the marketing rights we currently have or, if approved, an indication based on a successful outcome of the REDUCE-IT study. Even if we obtain marketing approval for additional indications, the FDA may impose restrictions on the products conditions for use, distribution or marketing and in some cases may impose
ongoing requirements for post-market surveillance, post-approval studies or clinical trials. Also, the number of actual patients with conditions within the scope of our marketing efforts may be smaller than we anticipate. If any such marketing right
or approved indication is narrower than we anticipate, the market potential for our product would suffer.

Our special protocol assessment, or SPA, agreement for ANCHOR was rescinded and our
SPA agreement for REDUCE-IT is not a guarantee of FDA approval of Vascepa for the proposed REDUCE-IT indication.

A SPA
is an evaluation by the FDA of a protocol with the goal of reaching an agreement that the Phase 3 trial protocol design, clinical endpoints, and statistical analyses are acceptable to support regulatory approval of the drug product candidate with
respect to effectiveness for the indication studied. The ANCHOR trial was, and the REDUCE-IT trial is, being conducted under an SPA agreement with the FDA. In each case, the FDA agreed that, based on the information we submitted to the agency, the
design and planned analysis of the trial is adequate to support use of the conducted study as the primary basis for approval with respect to effectiveness. A SPA agreement is generally binding upon the FDA except in limited circumstances, such as if
the FDA identifies a substantial scientific issue essential to determining safety or efficacy after the study begins, or if the study sponsor fails to follow the protocol that was agreed upon with the FDA.

In October 2013, the FDA notified us that it rescinded the ANCHOR study SPA agreement because the FDA determined that a substantial
scientific issue essential to determining the effectiveness of Vascepa in the studied population was identified after testing began. In April 2015, we received a CRL from the FDA stating that the FDA determined not to approve label expansion
reflecting the ANCHOR clinical trial efficacy data at this time.

Thus, even though we have received regulatory approval of
Vascepa for the MARINE indication under an SPA agreement, our ANCHOR SPA agreement was rescinded and there is no assurance that the FDA will not rescind our REDUCE-IT SPA agreement. The inability to obtain marketing approval in the ANCHOR or
REDUCE-IT indications has and would prevent us from growing revenue more significantly, and it has had, and could continue to have, a material adverse effect on our operations and financial condition, including our ability to reach profitability.

The commercial value to us of sales of Vascepa under the DCS Agreement with Eddingpharm may be smaller than we
anticipate.

There can be no assurance as to the adequacy for commercial success under the DCS Agreement with
Eddingpharm. Even if we and Eddingpharm obtain marketing approval in countries within the China Territory, applicable regulatory agencies may impose restrictions on the products conditions for use, distribution or marketing and in some cases
may impose ongoing requirements for post-market surveillance, post-approval studies or clinical trials. Also, with regard to any indications for which we may gain approval in these countries, the number of actual patients with the condition included
in such approved indication may be smaller than we anticipate. If any such approved indication is narrower than we anticipate, the market potential in these countries for our product would suffer.

Our products and marketing efforts are subject to extensive post-approval government regulation.

Once a product candidate receives FDA marketing approval, numerous post-approval requirements apply. Among other things, the holder of an
approved NDA is subject to periodic and other monitoring and reporting obligations enforced by the FDA and other regulatory bodies, including obligations to monitor and report adverse events and instances of the failure of a product to meet the
specifications in the approved application. Application holders must also submit advertising and other promotional material to regulatory authorities and report on ongoing clinical trials.

With respect to sales and marketing activities including direct-to-healthcare provider and direct-to-consumer advertising and promotional
activities involving the internet, advertising and promotional materials must comply with FDA rules in addition to other applicable federal and local laws in the United States and in other countries. Our First Amendment ruling may cause the
government to scrutinize our promotional efforts or otherwise monitor our business more closely. Industry-sponsored scientific and educational activities also must comply

with FDA and other requirements. In the United States, the distribution of product samples to physicians must comply with the requirements of the U.S. Prescription Drug Marketing Act.
Manufacturing facilities remain subject to FDA inspection and must continue to adhere to the FDAs pharmaceutical current good manufacturing practice requirements, or cGMPs. Application holders must obtain FDA approval for product and
manufacturing changes, depending on the nature of the change. We also are subject to the new federal transparency requirements under the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act,
which require manufacturers of certain drugs, devices, biologics, and medical supplies to report to the Centers for Medicare & Medicaid Services, or CMS, information related to payments and other transfers of value to physicians and
teaching hospitals and physician ownership and investment interests. We may also be subject, directly or indirectly through our customers and partners, to various fraud and abuse laws, including, without limitation, the U.S. Anti-Kickback Statute,
U.S. False Claims Act, and similar state laws, which impact, among other things, our proposed sales, marketing, and scientific/educational grant programs. If we participate in the U.S. Medicaid Drug Rebate Program, the Federal Supply Schedule of the
U.S. Department of Veterans Affairs, or other government drug programs, we will be subject to complex laws and regulations regarding reporting and payment obligations. We must also comply with requirements to collect and report adverse events and
product complaints associated with our products. For example, in September 2014, we participated in a routine inspection from the FDA in which the FDA made observations on perceived deficiencies related to our processes for collection and processing
of adverse events. We have responded to FDA with respect to these observations and continue to work with FDA to show that we have improved related systems and, given we received communication from the FDA that it considers this matter to be closed,
we believe that we have demonstrated to FDA that we have adequately responded to these observations. Our activities are also potentially subject to U.S. federal and state consumer protection and unfair competition laws. Similar requirements exist in
many of these areas in other countries.

Depending on the circumstances, failure to meet these post-approval requirements can
result in criminal prosecution, fines or other penalties, injunctions, recall or seizure of products, total or partial suspension of production, denial or withdrawal of pre-marketing product approvals, or refusal to allow us to enter into supply
contracts, including government contracts. We may also be held responsible for the non-compliance of our partners, such as Kowa Pharmaceuticals America, Inc. In addition, even if we comply with FDA and other requirements, new information regarding
the safety or effectiveness of a product could lead the FDA to modify or withdraw a product approval. Adverse regulatory action, whether pre- or post-approval, can potentially lead to product liability claims and increase our product liability
exposure. We must also compete against other products in qualifying for coverage and reimbursement under applicable third-party payment and insurance programs. In addition, all of the above factors may also apply to any regulatory approval for
Vascepa obtained within the China Territory under the DCS agreement with Eddingpharm. Given our inexperience with marketing and commercializing products in the China Territory, we will need to rely on Eddingpharm to assist us in dealing with any
such issues.

The FDA and other regulatory agencies strictly regulate the promotional claims that may be made about
prescription products. If we or Kowa Pharmaceuticals America, Inc. are found to have improperly promoted uses of Vascepa, we may become subject to significant fines and other liability. The government may seek to find means to prevent our promotion
of truthful and non-misleading information beyond our current court ruling.

The FDA and other regulatory agencies
strictly regulate the promotional claims that may be made about prescription products. In particular, in general, the U.S. governments position has been that a product may not be promoted for uses that are not approved by the FDA as reflected
in the products approved labeling. Even though we received FDA marketing approval for Vascepa for the MARINE indication and we believe our recent First Amendment court ruling affords us a degree of protection for other promotional efforts,
physicians may still prescribe Vascepa to their patients for use in the treatment of conditions that are not included as part of the indication statement in our FDA-approved Vascepa label or our court ruling. If we are found to have promoted Vascepa
outside the terms of the court ruling or in violation of what federal or state government may determine

to be acceptable, we may become subject to significant government fines and other related liability, such as under the False Claims Act or other theories of liability. Government may also seek to
hold us responsible for the non-compliance of our co-promotion partner, Kowa Pharmaceuticals America, Inc., or our ex-U.S. commercialization partner, Eddingpharm. For example, the Federal government has levied large civil and criminal fines against
companies for alleged improper promotion and has enjoined several companies from engaging in off-label promotion. The FDA has also requested that companies enter into consent decrees or permanent injunctions under which specified promotional conduct
is changed or curtailed.

In addition, incentives exist under applicable laws that encourage competitors, employees and
physicians to report violations of rules governing promotional activities for pharmaceutical products. These incentives could lead to so-called whistleblower lawsuits as part of which such persons seek to collect a portion of moneys allegedly
overbilled to government agencies due to, for example, promotion of pharmaceutical products beyond labeled claims. These incentives could also lead to suits that we have mischaracterized a competitors product in the marketplace and may, as a
result, be sued for alleged damages to our competitors. Such lawsuits, whether with or without merit, are typically time-consuming and costly to defend. Such suits may also result in related shareholder lawsuits, which are also costly to defend.

Even though we have the benefit of a preliminary ruling and may be ultimately successful with a final settlement or final
ruling in our current litigation related to promotion beyond FDA-approved labeling, our promotion would still be subject to a high, perhaps abnormally high, degree of scrutiny to ensure that our promotion remains within the permitted scope.
Likewise, federal or state government may seek to find other means to prevent our promotion of truthful and non-misleading information.

The REDUCE-IT cardiovascular outcomes trial may fail to show that Vascepa can reduce major cardiovascular events in an at-risk patient population on statin therapy, and the long-term clinical
results of Vascepa may not be consistent with the clinical results we observed in our Phase 3 clinical trial, in which case our sales of Vascepa may then suffer.

In accordance with the SPA agreements for our MARINE and ANCHOR trials, efficacy was evaluated in these trials compared to placebo at twelve weeks. No placebo-controlled studies have been conducted
regarding the long-term effect of Vascepa on lipids, and no outcomes study has been conducted evaluating Vascepa. The REDUCE-IT study is designed to evaluate the efficacy of Vascepa in reducing major cardiovascular events in an at-risk patient
population on statin therapy.

Outcomes studies of certain other lipid-modifying therapies have failed to achieve the
endpoints of such studies. For example, in 2010, the results of the ACCORD-Lipid trial were published. This trial studied the effect of adding fenofibrate onto open-label simvastatin therapy on cardiovascular outcomes. The addition of fenofibrate
did not show any treatment benefit on cardiovascular outcomes over simvastatin monotherapy in this study. In 2011, the results of the AIM-HIGH trial were published. This trial studied the effect of adding a second lipid-altering agent,
extended-release niacin, to simvastatin therapy on cardiovascular outcomes in people at high risk for cardiovascular events. No significant incremental treatment benefit with extended-release niacin was observed. In addition, in September 2012,
researchers published in the Journal of the American Medical Association, or JAMA, the results of a retrospective meta-analysis of twenty previously conducted studies regarding the use of omega-3 supplements across various patient
populations. This meta-analysis suggested that the use of such supplements was not associated with a lower risk of all-cause death, cardiac death, sudden death, heart attack, or stroke. We believe the results of these studies may not be directly
applicable to the use of Vascepa over time. For instance, the outcomes studies for fenofibrates and niacin were conducted in patient populations in which the majority of patients studied had triglycerides below 200 mg/dL and fenofibrates and niacin
are believed to work differently than Vascepa in the body and do not have as favorable a side-effect profile, and nineteen of the twenty studies included in the JAMA meta-analysis involved the use of omega-3 supplements containing a mixture
of EPA and DHA, and most were evaluated at relatively lower doses. In addition, in May 2013, The New England Journal of Medicine published the results of an outcomes study of

1 gram per day of an omega-3 acid ethyl ester composition. In that study, the composition failed to show a benefit in reducing the rate of death from cardiovascular causes or hospitalization for
cardiovascular causes when administered to patients with cardiovascular risk factors under different study conditions than in the REDUCE-IT study. Vascepa is comprised of highly-pure ethyl-EPA, and has been approved by the FDA for use in adult
patients with severe hypertriglyceridemia at a dose of 4 grams per day and is being studied in REDUCE-IT at 4 grams per day.

The only other outcomes study involving the use of a highly-pure formulation of ethyl-EPA, called the Japan EPA Lipid Intervention Study (JELIS), suggested that use of a highly-pure formulation of
ethyl-EPA in Japan, when used in conjunction with statins, reduced cardiovascular events by 19% compared to the use of statins alone. However, there are several limitations to the JELIS study. First, the patient population was exclusively Japanese,
the majority of the participants were women, and at baseline patients had a much higher LDL, limiting its generalizability to the intended target population. Also, a low dose of statins was used. It is unknown whether the positive treatment effects
would have persisted if these patients had been optimally treated with statins using contemporary LDL targets in the United States. In addition, JELIS was an open-label trial, which could influence patient and physician behavior and reporting of
symptoms, decisions regarding hospitalization, and referral of events for adjudication. This may be particularly relevant since hospitalization for unstable angina was a primary contributor of the overall positive result, and is considered a softer
endpoint than fatal cardiovascular events.

Further, FDA determined that JELIS results could not be used as support for or
against the use of triglyceride levels as a surrogate for cardiovascular risk reduction. Patients treated with EPA and statin in JELIS achieved triglyceride levels that were only 5% lower, on average, than those achieved among patients treated with
statin alone; however, the reduction in cardiovascular risk in the primary endpoint analysis was 19%. Likewise, within the primary and secondary prevention sub-analyses, triglyceride levels were lowered only 5% on average in the EPA plus statin
group compared with the statin alone group; however, the relative risk reduction was 53% in the primary prevention population with elevated triglyceride (> 150 mg/dL) and low HDL-C (< 40
mg/dL) levels and 23% in the secondary prevention population with established coronary artery disease. These large differences in magnitude between triglyceride reduction and risk reduction in JELIS suggest that the effects of EPA on triglyceride
levels alone may not be responsible for, or predict, the observed differences in cardiovascular events between treatment groups in JELIS. JELIS was not designed to evaluate primary and secondary prevention populations. It is possible that the
putative cardioprotective effects of EPA observed in JELIS are due not to a single mode of action, such as triglyceride lowering, but rather to multiple mechanisms working together, such as purported beneficial effects on multiple atherosclerosis
processes, including endothelial function, oxidative stress, foam cell formation, inflammation/cytokines, plaque formation/progression, platelet aggregation, thrombus formation, and plaque rupture. The REDUCE-IT study is needed to determine the
clinical benefit, if any, of EPA therapy in statin-treated patients with elevated triglyceride levels.

Although we believe
the results of the JAMA meta-analysis and other studies are not directly applicable to the potential long-term clinical experience with Vascepa, there can be no assurance that the endpoints of the REDUCE-IT cardiovascular outcomes study will
be achieved or that the lipid-modifying effects of Vascepa in REDUCE-IT or any other study of Vascepa will not be subject to variation beyond twelve weeks. If the REDUCE-IT trial fails to achieve its clinical endpoints or if the results of these
long-term studies are not consistent with the 12-week clinical results, it could prevent us from expanding the label of any approved product or even call into question the efficacy of any approved product.

The prospective interim efficacy and safety analysis of the REDUCE-IT cardiovascular
outcomes trial may not be completed in the contemplated timeframe in 2016 and may not demonstrate to the independent committee monitoring the study a sufficient benefit risk result to warrant the independent committee recommending stopping the study
early for overwhelming efficacy. The study may also be stopped for futility or for safety concerns.

In accordance with
the SPA agreement for our REDUCE-IT cardiovascular outcomes trial, an interim review of the efficacy and safety results of the trial is scheduled to occur upon reaching 60% of the target aggregate number of cardiovascular events. We currently expect
this interim review by the studys independent data monitoring committee (DMC) to occur during 2016 based on our understanding of the current event rates in the study and expected future event rates. It may actually take longer to reach the
targeted number of events, which would delay the DMC assessment of data for the interim analysis.

Further, as is typical of
interim analyses, the statistical threshold for defining overwhelming efficacy on the primary endpoint that would call for stopping the study early in connection with such analysis is considerably higher than the threshold for defining statistical
significance after the expected completion of the study in 2017. We do not expect the study to be stopped due to overwhelming efficacy at this interim look. We have instructed the DMC to not recommend stopping the study early based only upon
achieving statistical significance for the primary endpoint, but to ensure that statistical significance is also achieved for certain subpopulations before recommending that the study be stopped early for overwhelming efficacy. For example, even if
the appropriate studied cardiovascular events in the trial occur at sufficiently low rates in the active, Vascepa, group as compared to the placebo group such that the study would be a success at completion, the more rigorous statistical analysis
applied by the DMC at the interim analysis may not warrant stoppage of the study for overwhelming efficacy in connection with the interim analysis. The study may also be stopped pursuant to recommendation by the DMC at this interim analysis for lack
of signals of a favorable result at completion, so called stoppage for futility.

Moreover, it is the DMC that will make the
formal recommendation as to whether to stop the study early or continue as planned. Amarin is blinded to the interim analysis and is informed by the DMC of the recommendation to stop the study or to continue as planned. The DMC may consider factors
outside the pre-specified statistical analysis plan when assessing whether to continue the study as planned. For example, even if study results are sufficiently positive at the interim analysis to demonstrate overwhelming efficacy, the DMC at its
discretion may recommend continuation of the study as planned with the goal of arriving at more robust results at the planned study completion if it believes that waiting for more robust results outweighs the potential medical benefit of stopping
and unblinding the study early.

The DMC has multiple times per year assessed safety data generated in the ongoing study and
has thus far recommended to continue the study as planned. Thus, multiple safety analyses to date have not warranted study stoppage. Nevertheless, the study may be stopped at any time based on recommendations of the DMC due to safety concerns
identified by the DMC during its ongoing and regularly scheduled safety data assessments.

We may not be successful in
developing or marketing future products if we cannot meet the extensive regulatory requirements of the FDA and other regulatory agencies for quality, safety and efficacy.

The success of our research and development efforts is dependent in part upon our ability, and the ability of our partners or potential
partners, to meet regulatory requirements in the jurisdictions where we or our partners or potential partners ultimately intend to sell such products once approved. The development, manufacture and marketing of pharmaceutical products are subject to
extensive regulation by governmental authorities in the United States, the China Territory under the DCS Agreement with Eddingpharm, the European Union, Japan and elsewhere. In the United States, the FDA generally requires pre-clinical testing and
clinical trials of each drug to establish its safety and efficacy and extensive pharmaceutical development to ensure its quality before its introduction into the market. Regulatory authorities in other jurisdictions impose similar requirements. The
process of obtaining regulatory approvals is lengthy and expensive and the issuance of such approvals is

uncertain. The commencement and rate of completion of clinical trials and the timing of obtaining marketing approval from regulatory authorities may be delayed by many factors, including:



the lack of efficacy during clinical trials;



the inability to manufacture sufficient quantities of qualified materials under cGMPs for use in clinical trials;



slower than expected rates of patient recruitment;



the inability to observe patients adequately after treatment;



changes in regulatory requirements for clinical or preclinical studies;



the emergence of unforeseen safety issues in clinical or preclinical studies;



delay, suspension, or termination of a trial by the institutional review board responsible for overseeing the study at a particular study site;



unanticipated changes to the requirements imposed by regulatory authorities on the extent, nature or timing of studies to be conducted on quality,
safety and efficacy;



government or regulatory delays or clinical holds requiring suspension or termination of a trial; and



political instability affecting our clinical trial sites, such as the potential for political unrest affecting our REDUCE-IT clinical trial sites in
the Ukraine and Russia.

Even if we obtain positive results from early stage pre-clinical or clinical
trials, we may not achieve the same success in future trials. Clinical trials that we or potential partners conduct may not provide sufficient safety and efficacy data to obtain the requisite regulatory approvals for product candidates. The failure
of clinical trials to demonstrate safety and efficacy for our desired indications could harm the development of that product candidate as well as other product candidates, and our business and results of operations would suffer. For example, the
efficacy results of our Vascepa Phase 3 clinical trials for the treatment of Huntingtons disease were negative. As a result, we stopped development of that product candidate, revised our clinical strategy and shifted our focus to develop
Vascepa for use in the treatment of cardiovascular disease.

Any approvals that are obtained may be limited in scope, may
require additional post-approval studies or may require the addition of labeling statements focusing on product safety that could affect the commercial potential for our product candidates. Any of these or similar circumstances could adversely
affect our ability to earn revenues from the sale of such products. Even in circumstances where products are approved by a regulatory body for sale, the regulatory or legal requirements may change over time, or new safety or efficacy information may
be identified concerning a product, which may lead to the withdrawal of a product from the market or similar use restrictions. The discovery of previously unknown problems with a product or in connection with the manufacturer of products may result
in restrictions on that product or manufacturer, including withdrawal of the product from the market, which would have a negative impact on our potential revenue stream.

Legislative or regulatory reform of the healthcare system in the United States and foreign jurisdictions may affect our ability to profitably sell Vascepa.

Our ability to commercialize our future products successfully, alone or with collaborators, will depend in part on the extent to which
coverage and reimbursement for the products will be available from government and health administration authorities, private health insurers and other third-party payors. The continuing efforts of the U.S. and foreign governments, insurance
companies, managed care organizations and other payors of healthcare services to contain or reduce healthcare costs may adversely affect our ability to set prices for our products which we believe are fair, and our ability to generate revenues and
achieve and maintain profitability.

Specifically, in both the United States and some foreign jurisdictions, there have been a
number of legislative and regulatory proposals to change the healthcare system in ways that could affect our ability to sell

our products profitably. For example, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, or collectively the PPACA, enacted in March
2010, substantially changes the way healthcare is financed by both governmental and private insurers. Among other cost-containment measures, PPACA establishes:



An annual, nondeductible fee on any entity that manufactures or imports certain branded prescription drugs and biologic agents;



A new Medicare Part D coverage gap discount program, in which pharmaceutical manufacturers who wish to have their drugs covered under Part D must offer
discounts to eligible beneficiaries during their coverage gap period; and



A new formula that increases the rebates a manufacturer must pay under the Medicaid Drug Rebate Program.

We expect further federal and state proposals and healthcare reforms to continue to be proposed by legislators, which could limit the
prices that can be charged for the products we develop and may limit our commercial opportunity.

The continuing efforts of
government and other third-party payors to further contain or reduce the costs of healthcare through various means may limit our commercial opportunity. It will be time consuming and expensive for us to go through the process of seeking coverage and
reimbursement from Medicare and private payors. Our products may not be considered cost effective, and government and third-party private health insurance coverage and reimbursement may not be available to patients for any of our future products or
sufficient to allow us to sell our products on a competitive and profitable basis. Our results of operations could be adversely affected by PPACA and by other healthcare reforms that may be enacted or adopted in the future. In addition, increasing
emphasis on managed care in the United States will continue to put pressure on the pricing of pharmaceutical products. Cost control initiatives could decrease the price that we or any potential collaborators could receive for any of our future
products and could adversely affect our profitability.

In some foreign countries, including major markets in the European
Union and Japan, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take 6 to 12 months or longer after the receipt of regulatory marketing
approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct a pharmacoeconomic study that compares the cost-effectiveness of Vascepa to other available therapies. Such pharmacoeconomic studies
can be costly and the results uncertain. Our business could be harmed if reimbursement of our products is unavailable or limited in scope or amount or if pricing is set at unsatisfactory levels.

As we evolve from a company primarily involved in research and development to a company also focused on establishing an
infrastructure for commercializing Vascepa, we may encounter difficulties in managing our growth and expanding our operations successfully.

We hired and trained a professional sales force of approximately 275 sales representatives and commenced our commercial launch of Vascepa in the MARINE indication in the United States in early January
2013. The process of establishing a commercial infrastructure is difficult, expensive and time-consuming. Our October 2013 worldwide reduction in force, which included the termination of approximately 50% of the then-staffed sales force, has made
this process more difficult. As our operations expand with the anticipated growth of our produce sales, we expect that we will need to manage additional relationships with various collaborative partners, suppliers and other third parties. Future
growth will impose significant added responsibilities on members of management, including the need to identify, recruit, maintain and integrate additional employees. Our future financial performance and our ability to commercialize Vascepa and to
compete effectively will depend, in part, on our ability to manage our future growth effectively. To that end, we must be able to manage our development

efforts effectively, and hire, train, integrate and retain additional management, administrative and sales and marketing personnel. We may not be able to accomplish these tasks, and our failure
to accomplish any of them could prevent us from successfully growing our company.

Risks Related to our Reliance on Third Parties

Our supply of product for commercial supply and clinical trials is dependent upon relationships with third-party
manufacturers and key suppliers.

We have no in-house manufacturing capacity and rely on contract manufacturers for our
clinical and commercial product supply. We cannot assure you that we will successfully manufacture any product we may develop, either independently or under manufacturing arrangements, if any, with our third-party manufacturers. Moreover, if any
manufacturer should cease doing business with us or experience delays, shortages of supply or excessive demands on their capacity, we may not be able to obtain adequate quantities of product in a timely manner, or at all.

Any manufacturing problem, natural disaster affecting manufacturing facilities, or the loss of a contract manufacturer could be
disruptive to our operations and result in lost sales. Additionally, we will be reliant on third parties to supply the raw materials needed to manufacture Vascepa. Any reliance on suppliers may involve several risks, including a potential inability
to obtain critical materials and reduced control over production costs, delivery schedules, reliability and quality. Any unanticipated disruption to future contract manufacture caused by problems at suppliers could delay shipment of products,
increase our cost of goods sold and result in lost sales. If our suppliers were unable to supply us with adequate volumes of active pharmaceutical ingredient (drug substance) or encapsulated bulk product (drug product), it would have a material
adverse effect on our ability to continue to commercialize Vascepa.

We initially purchased all of our supply of the bulk
compound (ethyl-EPA), which constitutes the only active pharmaceutical ingredient, or API, of Vascepa, from a single supplier, Nisshin Pharma, Inc., or Nisshin, located in Japan. Nisshin was approved by the FDA as a Vascepa API supplier as part of
our FDA marketing approval for the MARINE indication in July 2012. In April 2013, we announced the approval by the FDA of Chemport, Inc. and BASF (formerly Equateq Limited) as additional Vascepa API suppliers. We terminated our agreement with BASF
due to its inability to meet the agreement requirements, may enter into a new development and supply agreement with BASF, and may purchase API from BASF. In 2014, we obtained sNDA approval of a fourth supplier of API, which includes the
manufacturing facility of Finorga SAS (Novasep). We currently purchase and use commercial supply from Novasep, Chemport, and Nisshin. Each of the API manufacturers obtains supply of the key raw material to manufacture API from other third-party
sources of supply.

While we have contractual freedom to source the API for Vascepa and have entered into supply agreements
with multiple suppliers who also rely on other third-party suppliers of the key raw material to manufacture the API for Vascepa, Novasep, Nisshin and Chemport currently supply all of our API for Vascepa. Our strategy in adding API suppliers beyond
Nisshin has been to expand manufacturing capacity and to partially mitigate the risk of reliance on any single supplier.

Expanding manufacturing capacity and qualifying such capacity is difficult and subject to numerous regulations and other operational
challenges. The resources of our suppliers vary and are limited; costs associated with projected expansion and qualification can be significant. For example, Chemport, which was approved as one of our API suppliers in April 2013, is a privately-held
company and their commitment to Vascepa supply has required them to seek additional resources. There can be no assurance that the expansion plans of any of our suppliers will be successful. Our aggregate capacity to produce API is dependent upon the
qualification of our API suppliers. Each of our API suppliers has outlined plans for potential further capacity expansion. If no additional API supplier is approved by the FDA, our API supply will be limited to the API we purchase from previously
approved suppliers. If our third-party manufacturing capacity is not expanded and compliant with

applicable regulatory requirements, we may not be able to supply sufficient quantities of Vascepa to meet anticipated demand. We cannot assure you that we can contract with any future
manufacturer on acceptable terms or that any such alternative supplier will not require capital investment from us in order for them to meet our requirements. Alternatively, our purchase of supply may exceed actual demand for Vascepa.

We currently have encapsulation agreements with three commercial API encapsulators for the encapsulation of Vascepa: Patheon, Inc.
(formerly Banner Pharmacaps), Catalent Pharma Solutions, and Capsugel Plöermel SAS. These companies have qualified their manufacturing processes and are capable of manufacturing Vascepa. There can be no guarantee that additional other suppliers
with which we have contracted to encapsulate API will be qualified to manufacture the product to our specifications or that these and any future suppliers will have the manufacturing capacity to meeting anticipated demand for Vascepa. We cannot
assure you that we can contract with any future manufacturer on acceptable terms or that any such alternative supplier will not require capital investment from us in order for them to meet our requirements.

We may not be able to maintain our exclusivity with our certain third-party Vascepa suppliers if we do not meet minimum purchase
obligations due to lower than anticipated sales of Vascepa.

Certain of our agreements with our suppliers include
minimum purchase obligations and limited exclusivity provisions based on such minimum purchase obligations. If we do not meet the respective minimum purchase obligations in our supply agreements, our suppliers, in certain cases, will be free to sell
the active pharmaceutical ingredient of Vascepa to potential competitors. Similarly if we terminate certain of our supply agreements, such suppliers may be free to sell the active pharmaceutical ingredient of Vascepa to potential competitors of
Vascepa. While we anticipate that intellectual property barriers and FDA regulatory exclusivity will be the primary means to protect the commercial potential of Vascepa, the availability of Vascepa active pharmaceutical ingredient from our suppliers
to our potential competitors would make our competitors entry into the market easier and more attractive.

We have
limited experience with the commercial sale of Vascepa, and such inexperience may cause us to purchase too much or not enough supply to satisfy actual demand, which could have a material adverse effect on our financial results and financial
condition.

Certain of our agreements with our suppliers include minimum purchase obligations and limited exclusivity
provisions. These purchases are generally made on the basis of rolling twelve-month forecasts which in part are binding on us and the balance of which are subject to adjustment by us subject to certain limitations. Certain of our agreements also
include contractual minimum purchase commitments regardless of the rolling twelve-month forecasts. We have limited experience with the commercial sale of Vascepa, and as such expectations regarding expected demand may be wrong. We may not purchase
sufficient quantities of Vascepa to meet actual demand or our purchase of supply may exceed actual demand. In either case, such event could have a material adverse effect on our financial results and financial condition.

The manufacture and packaging of pharmaceutical products such as Vascepa are subject to FDA requirements and those of similar
foreign regulatory bodies. If we or our third-party manufacturers fail to satisfy these requirements, our product development and commercialization efforts may be materially harmed.

The manufacture and packaging of pharmaceutical products, such as Vascepa, are regulated by the FDA and similar foreign regulatory bodies
and must be conducted in accordance with the FDAs pharmaceutical current good manufacturing practices, or cGMPs, and comparable requirements of foreign regulatory bodies. There are a limited number of manufacturers that operate under these
cGMPs regulations who are both capable of manufacturing Vascepa and willing to do so. Failure by us or our third-party manufacturers to comply with applicable regulations, requirements, or guidelines could result in sanctions being imposed on us,
including fines, injunctions, civil penalties, failure of regulatory authorities to grant marketing approval of our products, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of product, operating restrictions

and criminal prosecutions, any of which could significantly and adversely affect our business. For example, Nisshin may expand its capacity to supply API to us by further expanding their current
facility. If we are not able to manufacture Vascepa to required specifications through our current and potential API suppliers, we may be delayed in successfully supplying the product to meet anticipated demand and our anticipated future revenues
and financial results may be materially adversely affected.

Changes in the manufacturing process or procedure, including a
change in the location where the product is manufactured or a change of a third-party manufacturer, may require prior FDA review and approval of the manufacturing process and procedures in accordance with the FDAs cGMPs. Any new facility may
be subject to a pre-approval inspection by the FDA and would again require us to demonstrate product comparability to the FDA. There are comparable foreign requirements. This review may be costly and time consuming and could delay or prevent the
launch of a product.

Furthermore, the FDA and foreign regulatory agencies require that we be able to consistently produce the
API and the finished product in commercial quantities and of specified quality on a repeated basis, including proven product stability, and document our ability to do so. This requirement is referred to as process validation. This includes stability
testing, measurement of impurities and testing of other product specifications by validated test methods. If the FDA does not consider the result of the process validation or required testing to be satisfactory, the commercial supply of Vascepa may
be delayed, or we may not be able to supply sufficient quantities of Vascepa to meet anticipated demand.

The FDA and similar
foreign regulatory bodies may also implement new standards, or change their interpretation and enforcement of existing standards and requirements, for manufacture, packaging or testing of products at any time. If we are unable to comply, we may be
subject to regulatory, civil actions or penalties which could significantly and adversely affect our business.

We rely
on third parties to conduct our clinical trials, and those third parties may not perform satisfactorily, including failing to meet established deadlines for the completion of such clinical trials.

Our reliance on third parties for clinical development activities reduces our control over these activities. However, if we sponsor
clinical trials, we are responsible for ensuring that each of our clinical trials is conducted in accordance with the general investigational plan and protocols for the trials. Moreover, the FDA requires us to comply with standards, commonly
referred to as good clinical practices, for conducting, recording, and reporting the results of clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of trial
participants are protected. Our reliance on third parties does not relieve us of these responsibilities and requirements. Furthermore, these third parties may also have relationships with other entities, some of which may be our competitors. If
these third parties do not successfully carry out their contractual duties or meet expected deadlines, we may be delayed in obtaining regulatory approvals for our product candidates and may be delayed in our efforts to successfully commercialize our
product candidates for targeted diseases.

We are dependent upon our collaboration with Eddingpharm to commercialize
Vascepa in certain regions outside of the United States, and if Eddingpharm fails to successfully fulfill its obligations, or is ineffective in its commercialization of Vascepa in the China Territory, or if our collaboration is terminated, our plans
to commercialize Vascepa outside of the United States may be adversely affected.

In February 2015, we entered into the
DCS Agreement with Eddingpharm, under which we granted exclusive rights to Eddingpharm to develop and commercialize Vascepa in the China Territory. We are dependent on Eddingpharm for certain regulatory filings outside of the United States with
respect to Vascepa, which may require conducting clinical trials in the China Territory to secure regulatory approval, as well as the commercialization of Vascepa outside of the United States. If Eddingpharm fails to perform its obligations under

the DCS Agreement or is ineffective in its commercialization of Vascepa in the China Territory or if we fail to effectively manage our relationship with Eddingpharm, our ability to and the extent
to which we commercialize and obtain certain regulatory approvals of Vascepa outside of the United States would be significantly harmed.

In addition, Eddingpharm has the right to terminate the agreement under certain conditions. If Eddingpharm terminates the DCS Agreement, we would be required to either enter into alternative arrangements
with third parties to commercialize Vascepa in the China Territory, which we may be unable to do, or to increase our internal infrastructure, both of which would likely result in significant additional expense and delay or termination of our Vascepa
clinical development programs outside of the United States.

Risks Related to our Intellectual Property

We are dependent on patents, proprietary rights and confidentiality to protect the commercial potential of Vascepa.

Our success depends in part on our ability to obtain and maintain intellectual property protection for our drug
candidates, technology and know-how, and to operate without infringing the proprietary rights of others. Our ability to successfully implement our business plan and to protect our products with our intellectual property will depend in large part on
our ability to:



obtain, defend and maintain patent protection and market exclusivity for our current and future products;



preserve any trade secrets relating to our current and future products;



acquire patented or patentable products and technologies; and



operate without infringing the proprietary rights of third parties.

Amarin has prosecuted, and is currently prosecuting, multiple patent applications to protect the intellectual property developed during
the Vascepa cardiovascular program. As of the date of this report, we had 46 patent applications in the United States that have been either issued or allowed and more than 30 additional patent applications are pending in the United States. Such
46 allowed and issued applications include the following:



2 issued U.S. patents directed to a pharmaceutical composition of Vascepa in a capsule that have terms that expire in 2020 and 2030, respectively,

A Notice of Allowance is issued after the USPTO makes a determination that a patent can be
granted from an application. A Notice of Allowance does not afford patent protection until the underlying patent is issued by the USPTO. No assurance can be given that applications with issued notices of allowance will be issued as patents or that
any of our pending patent applications will issue as patents. No assurance can be given that, if and when issued, our patents will prevent competitors from competing with Vascepa. We are also pursuing patent applications related to Vascepa in
multiple jurisdictions outside the United States. We may be dependent in some cases upon third-party licensors to pursue filing, prosecution and maintenance of patent rights or applications owned or controlled by those parties. It is possible that
third parties will obtain patents or other proprietary rights that might be necessary or useful to us. In cases where third parties are first to invent a particular product or technology, or first to file after various provisions of the America
Invents Act of 2011 went into effect on March 16, 2013, it is possible that those parties will obtain patents that will be sufficiently broad so as to prevent us from utilizing such technology or commercializing our current and future products.

Although we intend to make reasonable efforts to protect our current and future intellectual property rights and to ensure
that any proprietary technology we acquire or develop does not infringe the rights of other parties, we may not be able to ascertain the existence of all potentially conflicting claims. Therefore, there is a risk that third parties may make claims
of infringement against our current or future products or technologies. In addition, third parties may be able to obtain patents that prevent the sale of our current or future products or require us to obtain a license and pay significant fees or
royalties in order to continue selling such products.

We may in the future discover the existence of products that infringe
patents that we own or that have been licensed to us. If we were to initiate legal proceedings against a third party to stop such an infringement, such proceedings could be costly and time consuming, regardless of the outcome. No assurances can be
given that we would prevail, and it is possible that, during such a proceeding, our patent rights could be held to be invalid, unenforceable or both. Although we intend to protect our trade secrets and proprietary know-how through confidentiality
agreements with our manufacturers, employees and consultants, we may not be able to prevent parties subject to such confidentiality agreements from breaching these agreements or third parties from independently developing or learning of our trade
secrets.

We anticipate that competitors may from time to time oppose our efforts to obtain patent protection for new
technologies or to submit patented technologies for regulatory approvals. Competitors may seek to oppose our patent applications to delay the approval process or to challenge our granted patents, for example, by requesting a reexamination of our
patent at the USPTO, or by filing an opposition in a foreign patent office, even if the opposition or challenge has little or no merit. Such proceedings are generally highly technical, expensive, and time consuming, and there can be no assurance
that such a challenge would not result in the narrowing or complete revocation of any patent of ours that was so challenged.

Our issued patents may not prevent competitors from competing with Vascepa, even if we seek to enforce our patent rights.

We plan to vigorously defend our rights under issued patents. For example, in March 2014, we filed a patent
infringement suit against Omthera Pharmaceuticals, Inc., and its parent company, AstraZeneca Pharmaceuticals LP. The suit sought injunctive relief and monetary damages for infringement of Amarins U.S. Patent No. 8,663,662. The complaint
alleged infringement of the patent arising from the expected launch of Epanova, a product that is expected to compete with Vascepa in the United States. The patent covers methods of lowering triglycerides by administering a pharmaceutical
composition that includes amounts of EPA as free acid, and no more than about 30% DHA. In November 2014, based on a representation from AstraZeneca Pharmaceuticals LP that the commercial launch of Epanova was not imminent, the court dismissed our
complaint, without prejudice (i.e., preserving our ability to later re-file the suit). The court required the defendant to notify us before any product launch. We intend to pursue this litigation vigorously and aggressively protect its intellectual
property rights. However, patent litigation is a time-consuming and costly process. There can be no assurance that we will be successful in enforcing this patent or that it will not be successfully challenged and invalidated. Even if we are
successful in enforcing this patent, the process could take years to reach conclusion.

Other drug companies may challenge the validity, enforceability, or both of our patents and
seek to design its products around our issued patent claims and gain marketing approval for generic versions of Vascepa or branded competitive products based on new clinical studies. The pharmaceutical industry is highly competitive and many of our
competitors have greater experience and resources than we have. Any such competition could undermine sales, marketing and collaboration efforts for Vascepa, and thus reduce, perhaps materially, the revenue potential for Vascepa.

Even if we are successful in enforcing our issued patents, we may incur substantial costs and divert managements time and attention
in pursuing these proceedings, which could have a material adverse effect on us. Patent litigation is costly and time consuming, and we may not have sufficient resources to bring these actions to a successful conclusion.

There can be no assurance that any of our pending patent applications relating to Vascepa or its use will issue as patents.

We have filed and are prosecuting numerous families of patent applications in the United States and internationally
with claims designed to protect the proprietary position of Vascepa. For certain of these patent families, we have filed multiple patent applications. Collectively the patent applications include numerous independent claims and dependent claims.
Several of our patent applications contain claims that are based upon what we believe are unexpected and favorable findings from the MARINE and ANCHOR trials. If granted, many of the resulting granted patents would expire in 2030 or beyond. However,
no assurance can be given that any of our pending patent applications will be granted or, if they grant, that they will prevent competitors from competing with Vascepa.

Securing patent protection for a product is a complex process involving many legal and factual questions. The patent applications we have filed in the United States and internationally are at varying
stages of examination, the timing of which is outside our control. The process to getting a patent granted can be lengthy and claims initially submitted are often modified in order to satisfy the requirements of the patent office. This process
includes written and public communication with the patent office. The process can also include direct discussions with the patent examiner. There can be no assurance that the patent office will accept our arguments with respect to any patent
application or with respect to any claim therein. The timing of the patent review process is independent of and has no effect on the timing of the FDAs review of our NDA or sNDA submissions. We cannot predict the timing or results of any
patent application. In addition, we may elect to submit, or the patent office may require, additional evidence to support certain of the claims we are pursuing. Furthermore, third parties may attempt to submit publications for consideration by the
patent office during examination of our patent applications. Providing such additional evidence and publications could prolong the patent offices review of our applications and result in us incurring additional costs. We cannot be certain what
commercial value any granted patent in our patent estate will provide to us.

Despite the use of confidentiality
agreements and/or proprietary rights agreements, which themselves may be of limited effectiveness, it may be difficult for us to protect our trade secrets.

In addition to our patent portfolio and strategy, we will also rely upon trade secrets and know-how to help protect our competitive position. We rely on trade secrets to protect technology in cases when
we believe patent protection is not appropriate or obtainable. However, trade secrets are difficult to protect. While we require certain of our academic collaborators, contractors and consultants to enter into confidentiality agreements, we may not
be able to adequately protect our trade secrets or other proprietary information.

Risks Related to our Business

If the estimates we make, or the assumptions on which we rely, in preparing our projected guidance prove inaccurate, our actual
results may vary from those reflected in our projections and accruals.

In January 2016, we issued financial and
business guidance, including preliminary (unaudited) 2015 revenue and year-end cash results as well as expected fiscal year 2016 total net revenue, which is based on estimates and

the judgment of management. Because of the inherent nature of estimates, there could be significant differences between our estimates and the actual amount of product demand. If, for any reason,
we are unable to realize our projected 2016 revenue, we may not realize our publicly announced financial guidance. If we fail to realize or if we change or update any element of our publicly disclosed financial guidance or other expectations about
our business, our stock price could decline in value.

We and certain of our current and former executive officers have
been named as defendants in a class action lawsuit that could result in substantial costs and divert managements attention.

The market price of our American Depositary Shares, or ADSs, declined significantly after the October 2013 decision by the FDA Advisory Committee to recommend against approval of Vascepa in the ANCHOR
indication. We and certain of our current and former executive officers and directors have been named as defendants in a class action lawsuit that generally alleges that we and certain of our current and former officers and directors violated
Sections 10(b) and/or 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder by making allegedly false and/or misleading statements or material omissions concerning the ANCHOR sNDA and related FDA regulatory approval
process in an effort to lead investors to believe that Vascepa would receive approval from the FDA in the ANCHOR indication. The complaints seek unspecified damages, interest, attorneys fees, and other costs.

We engaged in a vigorous defense of this lawsuit. On June 29, 2015, the Court granted our motion to dismiss the class action without
prejudice. The Court held that the plaintiffs failed to state a claim upon which relief could be granted and plaintiffs were given 30 days to refile an amended complaint.

On July 29, 2015, the plaintiffs filed an amended complaint. We again moved to dismiss, await a ruling on that motion and plan to continue with our vigorous defense. However, we are unable to predict
the outcome of this matter at this time. Moreover, while we expect insurance to cover any financial exposure from this litigation, the conclusion of this matter in a manner adverse to us could have a material adverse effect on our financial
condition and business. For example, we could incur substantial costs not covered by our directors and officers liability insurance, suffer a significant adverse impact on our reputation and divert managements attention and
resources from other priorities, including the execution of business plans and strategies that are important to our ability to grow our business, any of which could have a material adverse effect on our business. In addition, any of these matters
could require payments that are not covered by, or exceed the limits of, our available directors and officers liability insurance, which could have a material adverse effect on our operating results or financial condition.

Potential technological changes in our field of business create considerable uncertainty.

We are engaged in the biopharmaceutical field, which is characterized by extensive research efforts and rapid technological progress. New
developments in research are expected to continue at a rapid pace in both industry and academia. We cannot assure you that research and discoveries by others will not render some or all of our programs or product candidates uncompetitive or
obsolete. Our business strategy is based in part upon new and unproven technologies to the development of therapeutics to improve cardiovascular health. We cannot assure you that unforeseen problems will not develop with these technologies or
applications or that any commercially feasible products will ultimately be developed by us.

We are subject to potential
product liability.

Following the commercial launch of Vascepa, we will be subject to the potential risk of product
liability claims relating to the manufacturing and marketing of Vascepa. Any person who is injured as a result of using Vascepa may have a product liability claim against us without having to prove that we were at fault.

In addition, we could be subject to product liability claims by persons who took part in clinical trials involving our current or former
development stage products. A successful claim brought against us could have a material adverse effect on our business. We cannot guarantee that a product liability claim will not be asserted against us in the future.

We may become subject to liability in connection with the wind-down of our EN101
program.

In 2007, we purchased Ester Neurosciences Limited, an Israeli pharmaceutical company, and its lead product
candidate, EN101, an AChE-R mRNA inhibitor for the treatment of myasthenia gravis, or MG, a debilitating neuromuscular disease. In connection with the acquisition, we assumed a license to certain intellectual property assets related to EN101 from
the Yissum Research Development Company of The Hebrew University of Jerusalem. In keeping with our 2009 decision to re-focus our efforts on developing improved treatments for cardiovascular disease and cease development of all product candidates
outside of our cardiovascular disease focus, we amended the terms of our acquisition agreement with the original shareholders of Ester.

Following our decision to cease development of EN101, Yissum terminated its license agreement with us. In June 2011, Yissum announced that it had entered into a license agreement with BiolineRX Ltd for
the development of EN101 in a different indication, inflammatory bowel disease.

In 2011 and early 2012, but not after, we
received several communications on behalf of the former shareholders of Ester asserting that we are in breach of our agreement with them as it relates to alleged rights to share in the value of EN101 due to the fact that Yissum terminated its
license. We do not believe the circumstances presented constitute a breach of the agreement. If the dispute arises again, we plan to defend our position vigorously, but there can be no assurance as to the outcome of this dispute.

A change in our tax residence could have a negative effect on our future profitability.

Under current UK legislation, a company incorporated in England and Wales, or which is centrally managed and controlled in the UK, is
regarded as resident in the UK for taxation purposes. Under current Irish legislation, a company is regarded as resident for tax purposes in Ireland if it is centrally managed and controlled in Ireland, or, in certain circumstances, if it is
incorporated in Ireland. Where a company is treated as tax resident under the domestic laws of both the UK and Ireland then the provisions of article 4(3) of the Double Tax Convention between the UK and Ireland provides that such enterprise shall be
treated as resident only in the jurisdiction in which its place of effective management is situated. We have sought to conduct our affairs in such a way so as to be resident only in Ireland for tax purposes by virtue of having our place of effective
management situated in Ireland. Trading income of an Irish company is generally taxable at the Irish corporation tax rate of 12.5%. Non-trading income of an Irish company (e.g., interest income, rental income or other passive income) is taxable at a
rate of 25%.

However, we cannot assure you that we are or will continue to be resident only in Ireland for tax purposes. It
is possible that in the future, whether as a result of a change in law or the practice of any relevant tax authority or as a result of any change in the conduct of our affairs, we could become, or be regarded as having become resident in a
jurisdiction other than Ireland. Should we cease to be an Irish tax resident, we may be subject to a charge to Irish capital gains tax on our assets. Similarly, if the tax residency of any of our subsidiaries were to change from their current
jurisdiction for any of the reasons listed above, we may be subject to a charge to local capital gains tax charge on the assets.

The loss of key personnel could have an adverse effect on our business.

We are highly dependent upon the efforts of our senior management. The loss of the services of one or more members of senior management could have a material adverse effect on us. As a small company with
a streamlined management structure, the departure of any key person could have a significant impact and would be potentially disruptive to our business until such time as a suitable replacement is hired. Furthermore, because of the specialized
nature of our business, as our business plan progresses we will be highly dependent upon our ability to attract and retain qualified scientific, technical and key management personnel. As we evolve from a development stage company to a commercial
stage company we may experience turnover among members of our senior management team. We may have difficulty identifying and integrating new executives to replace any such

losses. There is intense competition for qualified personnel in the areas of our activities. In this environment, we may not be able to attract and retain the personnel necessary for the
development of our business, particularly if we do not achieve profitability. The failure to recruit key scientific, technical and management personnel would be detrimental to our ability to implement our business plan.

We could be adversely affected by our exposure to customer concentration risk.

A significant portion of our sales are to wholesalers in the pharmaceutical industry. Our top three customers accounted for 95% of gross
product sales for each of the years ended December 31, 2015 and 2014, and represented 95% and 96% of the gross accounts receivable balance as of December 31, 2015 and 2014, respectively. There can be no guarantee that we will be able to
sustain our accounts receivable or gross sales levels from our key customers. If, for any reason, we were to lose, or experience a decrease in the amount of business with our largest customers, whether directly or through our distributor
relationships, our financial condition and results of operations could be negatively affected.

Risks Related to our Financial Position and
Capital Requirements

We have a history of operating losses and anticipate that we will incur continued losses for an
indefinite period of time.

We have not yet reached profitability. For the fiscal years ended December 31, 2015,
2014, and 2013, we reported losses of approximately $149.1 million, $56.4 million, and $166.2 million, respectively, and we had an accumulated deficit as of December 31, 2015 of $1.1 billion. Substantially all of our operating losses resulted
from costs incurred in connection with our research and development programs, from general and administrative costs associated with our operations, costs related to the commercialization of Vascepa, and from non-cash losses on changes in the fair
value of warrant derivative liabilities. Additionally, as a result of our significant expenses relating to research and development and to commercialization, we expect to continue to incur significant operating losses for an indefinite period.
Because of the numerous risks and uncertainties associated with developing and commercializing pharmaceutical products, we are unable to predict the magnitude of these future losses. Our historic losses, combined with expected future losses, have
had and will continue to have an adverse effect on our cash resources, shareholders deficit and working capital.

Although we began generating revenue from Vascepa in January 2013, we may never be profitable.

Our ability to become profitable depends upon our ability to generate revenue. In January 2013, we began to generate revenue from the
marketing of Vascepa for use in the MARINE indication, but we may not be able to generate sufficient revenue to attain profitability. Our ability to generate profits on sales of Vascepa is subject to the market acceptance and commercial success of
Vascepa and our ability to manufacture commercial quantities of Vascepa through third parties at acceptable cost levels, and may also depend upon our ability to enter into one or more strategic collaborations to effectively market and sell Vascepa.

Even though Vascepa has been approved by the FDA for marketing in the United States in the MARINE indication, it may not gain
market acceptance or achieve commercial success and it may never be approved for the ANCHOR indication or any other indication. In addition, we anticipate continuing to incur significant costs associated with commercializing Vascepa. We may not
achieve profitability soon after generating product sales, if ever. If we are unable to generate sufficient product revenues, we will not become profitable and may be unable to continue operations without continued funding.

Our historical financial results do not form an accurate basis for assessing our current business.

As a consequence of the many years developing Vascepa for commercialization and the commercial launch of Vascepa in 2013 in the United
States, our historical financial results do not form an accurate basis upon which investors should base their assessment of our business and prospects. In addition, we expect that our costs will

increase substantially as we continue to commercialize Vascepa in the MARINE indication and with ANCHOR data and seek to obtain additional regulatory approval of Vascepa from continuation of the
REDUCE-IT cardiovascular outcomes study. Accordingly, our historical financial results reflect a substantially different business from that currently being conducted and from that expected in the future. In addition, we have a limited history of
obtaining regulatory approval for, and no demonstrated ability to successfully commercialize, a product candidate. Consequently, any predictions about our future performance may not be as accurate as they could be if we had a history of successfully
developing and commercializing pharmaceutical products.

Our operating results are unpredictable and may fluctuate. If
our operating results are below the expectations of securities analysts or investors, the trading price of our stock could decline.

Our operating results are difficult to predict and will likely fluctuate from quarter to quarter and year to year, and Vascepa prescription figures will likely fluctuate from month to month. Vascepa sales
are difficult to predict from period to period and as a result, you should not rely on Vascepa sales results in any period as being indicative of future performance, and sales of Vascepa may be below the expectation of securities analysts or
investors in the future. We believe that our quarterly and annual results of operations may be affected by a variety of factors, including:



the level of demand for Vascepa;



the extent to which coverage and reimbursement for Vascepa is available from government and health administration authorities, private health insurers,
managed care programs and other third-party payers;



the timing, cost and level of investment in our sales and marketing efforts to support Vascepa sales and the resulting effectiveness of those efforts
with our new co-promotion partner, Kowa Pharmaceuticals America, Inc.;



the timing and ability of Eddingpharm to development and commercialize Vascepa in the China Territory, including obtaining necessary regulatory
approvals and establishing marketing channels;

the results of the REDUCE-IT study or post-approval studies for Vascepa;



outcomes of litigation and other legal proceedings, including the lawsuit against the FDA to expand marketing claims for Vascepa, our NCE litigation,
shareholder litigation, regulatory matters and tax matters; and



our regulatory dialogue on the REDUCE-IT study.

We may require substantial additional resources to fund our operations. If we cannot find additional capital resources, we will have difficulty in operating as a going concern and growing our
business.

We currently operate with limited resources. We believe that our cash and cash equivalents balance of $107.0
million as of December 31, 2015 will be sufficient to fund our projected operations for at least the next twelve months. Depending on the level of cash generated from operations, additional capital may be required to sustain operations.

In order to fully realize the market potential of Vascepa, we may need to enter into a new strategic collaboration or raise
additional capital. We may also need additional capital to fully complete our REDUCE-IT cardiovascular outcomes trial.

Our
future capital requirements will depend on many factors, including:



revenue generated from the commercial sale of Vascepa;



the costs associated with commercializing Vascepa in the United States and for additional indications in the United States and in jurisdictions in
which we receive regulatory approval, if any, including the

cost of sales and marketing capabilities with our new co-promotion partner, Kowa Pharmaceuticals America, Inc., and the cost and timing of securing commercial supply of Vascepa and the timing of
entering into any new strategic collaboration with others relating to the commercialization of Vascepa, if at all, and the terms of any such collaboration;



the continued cost associated with our REDUCE-IT cardiovascular outcomes study;



continued costs associated with litigation and other legal proceedings;



the time and costs involved in obtaining additional regulatory approvals for Vascepa;



the extent to which we continue to develop internally, acquire or in-license new products, technologies or businesses; and



the cost of filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights.

If we require additional funds and adequate funds are not available to us in amounts or on terms acceptable to us or on a timely basis,
or at all, our commercialization efforts for Vascepa may suffer materially, and we may need to delay the advancement of the REDUCE-IT cardiovascular outcomes trial.

Continued negative economic conditions would likely have a negative effect on our ability to obtain financing on acceptable terms.

While we may seek additional funding through public or private financings, we may not be able to obtain financing on acceptable terms, or
at all. There can be no assurance that we will be able to access equity or credit markets in order to finance our current operations or expand development programs for Vascepa, or that there will not be a further deterioration in financial markets
and confidence in economies. We may also have to scale back or further restructure our operations. If we are unable to obtain additional funding on a timely basis, we may be required to curtail or terminate some or all of our research or development
programs or our commercialization strategies.

To the extent we are permitted under our
Purchase and Sale Agreement with BioPharma Secured Debt Fund II Holdings Cayman LP, or BioPharma, we may seek additional capital through a combination of private and public equity offerings, debt financings and collaboration, strategic and licensing
arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms may include liquidation or other preferences that adversely affect your
rights as a shareholder.

In January 2012, we issued $150 million in aggregate principal amount of 3.5% exchangeable senior
notes due 2032, or the 2012 Notes, $16.2 million of which was subsequently repaid. In May 2014, we entered into separate, privately negotiated exchange agreements with certain holders of the 2012 Notes pursuant to which Corsicanto exchanged $118.7
million in aggregate principal amount of the existing 2012 Notes for $118.7 million in aggregate principal amount of new 3.5% May 2014 Exchangeable Senior Notes due 2032, or the 2014 Notes. In the event of physical settlement, the remaining
2012 Notes and 2014 Notes would be exchangeable into a total of 1,714,270 ADSs and 45,666,925 ADSs, respectively.

In November
2015, we issued $31.3 million in aggregate principal amount of 3.5% exchangeable senior notes due 2032, or the 2015 Notes. In the event of physical settlement, the 2015 Notes would be exchangeable into a total of 12,025,385 ADSs.

Debt financing, if available, may involve agreements that include covenants limiting or
restricting our ability to take specific actions such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through collaboration, strategic alliance and licensing arrangements with third
parties, we may have to relinquish valuable rights to our technologies, Vascepa or product candidates beyond the rights we have already relinquished, or grant licenses on terms that are not favorable to us.

Potential business combinations or other strategic transactions may disrupt our business or divert managements attention.

On a regular basis, we explore potential business combination transactions, including an acquisition of us by a third
party, exclusive licenses of Vascepa or other strategic transactions or collaborations with third parties. For example, in March 2014, we entered into a co-promotion agreement with Kowa Pharmaceuticals America, Inc. related to the commercialization
of Vascepa in the United States. The consummation and performance of any such future transactions or collaborations will involve risks, such as:



diversion of managerial resources from day-to-day operations;



exposure to litigation from the counterparties to any such transaction, other third parties or our shareholders;



misjudgment with respect to the value;



higher than expected transaction costs; or



an inability to successfully consummate any such transaction or collaboration.

As a result of these risks, we may not be able to achieve the expected benefits of any such transaction or collaboration or deliver the
value thereof to our shareholders. If we are unsuccessful in consummating any such transaction or collaboration, we may be required to reevaluate our business only after we have incurred substantial expenses and devoted significant management time
and resources.

Risks Related to Ownership of our ADSs and Common Shares

The price of our ADSs and common shares may be volatile.

The stock market has from time to time experienced significant price and volume fluctuations that may be unrelated to the operating
performance of particular companies. In addition, the market prices of the securities of many pharmaceutical and medical technology companies have been especially volatile in the past, and this trend is expected to continue in the future.

As of February 20, 2016 we had 185,011,734 common shares outstanding including 183,074,916 shares held as ADSs and
1,936,818 held as common shares (which are not held in the form of ADSs). There is a risk that there may not be sufficient liquidity in the market to accommodate significant increases in selling activity or the sale of a large block of our
securities. Our ADSs have historically had limited trading volume, which may also result in volatility. If any of our large investors, such as the participants in our March 2015 private placement, seek to sell substantial amounts of our ADSs,
particularly if these sales are in a rapid or disorderly manner, or other investors perceive that these sales could occur, the market price of our ADSs could decrease significantly.

The market price of our ADSs and common shares may also be affected by factors such as:

The number of our ordinary shares, or ADSs representing such ordinary shares, outstanding may increase substantially as a result of our March 2015 private placement and the later consolidation and
redesignation of the Series A Preference Shares represented by Preference ADSs issued thereunder, and some of the investors may then beneficially own significant blocks of our ordinary shares; the ordinary shares and Series A Preference Shares
resulting from the private placement will be generally available for resale in the public market upon registration under the Securities Act.

In March and July 2015, we completed a private placement of American Depositary Shares in two tranches representing 352,150,790 and 38,867,180 Series A Preference Shares, respectively, each ten
(10) of which may be consolidated and redesignated into one (1) ordinary share in our capital. During the three months ended June 30, 2015, 62,833,330 preferred shares were converted, resulting in the issuance of 6,283,333 ordinary
shares. The consolidation and redesignation of the Series A Preference Shares currently outstanding would result in an additional 32,818,464 ordinary shares outstanding, resulting in substantial dilution to shareholders who held our ordinary shares
or ADSs representing such ordinary shares prior to the private placement. Although the Series A Preference Shares do not have voting rights, in general, upon consolidation and redesignation into ordinary shares some of the investors in the private
placement could then have significant influence over the outcome of any shareholder vote, including the election of directors and the approval of mergers or other business combination transactions.

Pursuant to the securities subscription agreements that we entered into with the investors in the private placement, we agreed to file
with the SEC a registration statement to register the resale of the Series A Preference Shares represented by American Depositary Shares issued in the private placement and the ordinary shares issuable upon the consolidation and consolidation and
redesignation of such Series A Preference Shares. Upon such registration and subsequent consolidation and redesignation, these securities will become generally available for immediate resale in the public market. The market price of our ordinary
shares could fall as a result of an increase in the number of shares available for sale in the public market.

Failure
to comply with our obligations under the March 2015 securities subscription agreements could result in our becoming liable for damages to certain investors under these agreements, including specified liquidated damages, which could be material in
amount.

Under the terms of the March 2015 securities subscription agreements, we are subject to various obligations,
failure to comply with which could result in our becoming liable to certain investors under these agreement for damages, which could be material in amount.

For example, under each of these agreements we have agreed to file and maintain the effectiveness of certain resale registration statements for ADSs representing the ordinary shares underlying the Series
A Preference shares we issued and sold under these agreements. Specifically, we have agreed to pay liquidated damages to the investors in the respective private placements if (a) the applicable resale registration statements we are required to
file are not declared effective within 120 days after the closing of the applicable private placement, or (b) after effectiveness and subject to certain specified exceptions, we suspend the use of the applicable registration statement or the
registration statement ceases to remain continuously effective as to all the securities for which it is required to be effective. We refer to each of these events as a registration default. Subject to the specified exceptions, for each 30-day period
or portion thereof during which a registration default

remains uncured, we are obligated to pay liquidated damages to each investor in cash in an amount equal to 1% of the aggregate subscription price paid by each such investor in the private
placement, up to a maximum of 8% of such aggregate subscription price. These amounts could be material, and any liquidated damages we are required to pay could have a material adverse effect on our financial condition.

In addition, under the securities subscription agreement dated as of March 5, 2015, we are required to offer to certain investors
party to that agreement an opportunity to participate in future equity and debt financings we may conduct from time to time, and to not publicly disclose the identity of the investors party to that agreement, subject to certain exceptions for
disclosures required in securities filings and under applicable law. If we fail to comply with these obligations we could become liable to these investors for damages, including specified liquidated damages. For example, following certain public
statements made by us on a quarterly conference call concerning the 2015 private placement, we agreed to specified liquidated damages in the event we are found to have violated the confidentiality provisions of the subscription agreement in the
future.

A share price of less than $1.00 may impact our NASDAQ listing.

If our closing bid price is less than $1.00 for 30 consecutive trading days, we would receive a NASDAQ staff deficiency letter indicating
that we are not in compliance with the minimum bid price requirement for continued listing. Such a letter would trigger an automatic 180 calendar day period within which the company could regain compliance. Compliance is regained at any time during
this period if the Amarin closing bid price is $1.00 per share or more for a minimum of 10 consecutive trading days. If we do not regain compliance during this period, our ADSs could be delisted from The NASDAQ Global Market, transferred to a
listing on The NASDAQ Capital Market, or delisted from the NASDAQ markets altogether. The failure to maintain our listing on The NASDAQ Global Market could harm the liquidity of our ADSs and could have an adverse effect on the market price of our
ADSs.

Actual or potential sales of our common shares by our employees, including members of our senior management team,
pursuant to pre-arranged stock trading plans could cause our stock price to fall or prevent it from increasing for numerous reasons, and actual or potential sales by such persons could be viewed negatively by other investors.

In accordance with the guidelines specified under Rule 10b5-1 of the Securities Exchange Act of 1934 and our policies regarding stock
transactions, a number of our directors and employees, including members of our senior management team, have adopted and may continue to adopt pre-arranged stock trading plans to sell a portion of our common stock. Generally, sales under such plans
by members of our senior management team and directors require public filings. Actual or potential sales of our ADSs by such persons could cause the price of our ADSs to fall or prevent it from increasing for numerous reasons. For example, a
substantial amount of our ADSs becoming available (or being perceived to become available) for sale in the public market could cause the market price of our ADSs to fall or prevent it from increasing. Also, actual or potential sales by such persons
could be viewed negatively by other investors.

We may be a passive foreign investment company, or PFIC, which would
result in adverse U.S. federal tax consequences to U.S. investors.

Amarin Corporation plc and certain of our
subsidiaries may be classified as passive foreign investment companies, or PFICs, for U.S. federal income tax purposes. The tests for determining PFIC status for a taxable year depend upon the relative values of certain categories of
assets and the relative amounts of certain kinds of income. The application of these factors depends upon our financial results, which are beyond our ability to predict or control, and which may be subject to legal and factual uncertainties.

We believe it is prudent to assume that we were classified as a PFIC in 2012. We do not believe that we were classified as a
PFIC in 2013, 2014 or 2015. Our status as a PFIC is subject to change in 2016 and future years.

If we are a PFIC, U.S. holders of notes, ordinary shares or ADSs would be subject to adverse
U.S. federal income tax consequences, such as ineligibility for any preferred tax rates on capital gains or on actual or deemed dividends, interest charges on certain taxes treated as deferred, and additional reporting requirements under U.S.
federal income tax laws and regulations. Whether or not U.S. holders of our ADSs make a timely QEF election or mark-to-market election may affect the U.S. federal income tax consequences to U.S. holders with respect to the
acquisition, ownership and disposition of Amarin ADSs and any distributions such U.S. Holders may receive. A QEF election and other elections that may mitigate the effect of our being classified as a PFIC are unavailable with respect to the notes.
Investors should consult their own tax advisors regarding all aspects of the application of the PFIC rules to the notes, ordinary shares and ADSs.

Pursuant to our December 2012 Purchase and Sale Agreement with BioPharma, we are obligated to make payments to BioPharma based on the
amount of our net product sales of Vascepa and any future products based on ethyl-EPA, or covered products, subject to certain quarterly caps.

Pursuant to this agreement, we may not, among other things: (i) incur indebtedness greater than a specified amount, which we refer to as the Indebtedness Covenant; (ii) pay a dividend or other
cash distribution, unless we have cash and cash equivalents in excess of a specified amount after such payment; (iii) amend or restate our memorandum and articles of association unless such amendments or restatements do not affect
BioPharmas interests under the transaction; (iv) encumber any of the collateral securing our performance under the agreement; and (v) abandon certain patent rights, in each case without the consent of BioPharma.

Upon a transaction resulting in a change of control of Amarin, as defined in the agreement, BioPharma will be automatically entitled to
receive any amounts not previously paid, up to our maximum repayment obligation. As defined in the agreement, change of control includes, among other things, (i) a greater than 50 percent change in the ownership of Amarin,
(ii) a sale or disposition of any collateral securing our debt with BioPharma and (iii), unless BioPharma has been paid a certain amount under the indebtedness, certain licensings of Vascepa to a third party for sale in the United States. The
acceleration of the payment obligation in the event of a change of control transaction may make us less attractive to potential acquirers, and the payment of such funds out of our available cash or acquisition proceeds would reduce acquisition
proceeds for our shareholders.

To secure our obligations under the agreement, we granted BioPharma a security interest in our
rights in patents, trademarks, trade names, domain names, copyrights, know-how and regulatory approvals related to the covered products, all books and records relating to the foregoing and all proceeds of the foregoing, which we refer to as the
collateral. If we (i) fail to deliver a payment when due and do not remedy that failure within specific notice period, (ii) fail to maintain a first-priority perfected security interest in the collateral in the United States and do not
remedy that failure after receiving notice of such failure or (iii) become subject to an event of bankruptcy, then BioPharma may attempt to collect the maximum amount payable by us under this agreement (after deducting any payments we have
already made).

There can be no assurance that we will not breach the covenants or other terms of, or that an event of default
will not occur under, this agreement and, if a breach or event of default occurs, there can be no assurance that we will be able to cure the breach within the time permitted. Any failure to pay our obligations when due, any breach or default of our
covenants or other obligations, or any other event that causes an acceleration of payment at a time when we do not have sufficient resources to meet these obligations, could have a material adverse effect on our business, results of operations,
financial condition and future viability.

Our existing indebtedness consists of $165.1 million in aggregate principal amount of 3.5% exchangeable senior notes
due 2032, $15.1 million of which relates to the January 2012 notes with provisions for the notes to

be put to us on or after January 19, 2017 and $118.7 million of May 2014 notes and $31.3 million of November 2015 notes, both with provisions for the notes to be redeemed by us on or after
January 19, 2018 or put to us by the holders on or after January 19, 2019.

Our indebtedness and the related annual
debt service requirements may adversely impact our business, operations and financial condition in the future. For example, they could:



increase our vulnerability to general adverse economic and industry conditions;



limit our ability to raise additional funds by borrowing or engaging in equity sales in order to fund future working capital, capital expenditures,
research and development and other general corporate requirements;



require us to dedicate a substantial portion of our cash to service payments on our debt; or



limit our flexibility to react to changes in our business and the industry in which we operate or to pursue certain strategic opportunities that may
present themselves.

The accounting for convertible debt securities that may be settled in cash, such
as our notes, could have a material effect on our reported financial results.

Under the FASB Accounting Standards
Codification, or ASC, we are required to separately account for the liability and equity components of the convertible debt instruments (such as the notes) that may be settled entirely or partially in cash upon conversion in a manner that reflects
the issuers economic interest cost. The effect of ASC on the accounting for our outstanding convertible notes may be that the equity component is required to be included in the additional paid-in capital section of stockholders equity on
our consolidated balance sheets and the value of the equity component would be treated as original issue discount for purposes of accounting for the debt component of the notes. As a result, we are required to record non-cash interest expense as a
result of the amortization of the discounted carrying value of the notes to their face amount over the term of the notes. We may be required to report higher interest expense in our financial results because ASC may require interest to include both
the current periods amortization of the debt discount and the instruments coupon interest, which could adversely affect our reported or future financial results and the trading price of our ADSs.

Servicing our debt may require a significant amount of cash, and we may not have sufficient cash flow from our business to provide the
funds sufficient to pay our substantial debt.

Our ability to make scheduled payments of the principal, to pay interest on or
to refinance our indebtedness, including the notes, depends on our future performance, which is subject to economic, financial, competitive and other factors beyond our control. Our business may not continue to generate cash flow from operations in
the future sufficient to service our debt and make necessary capital expenditures. If we are unable to generate such cash flow, we may be required to adopt one or more alternatives, such as selling assets, restructuring debt or obtaining additional
equity capital on terms that may be onerous or highly dilutive. Our ability to refinance our indebtedness will depend on the capital markets and our financial condition at such time. We may not be able to engage in any of these activities or engage
in these activities on desirable terms, which could result in a default on our debt obligations, including the notes, and have a material adverse effect on the trading price of our ADSs.

We may be able to incur substantial additional debt in the future, subject to the restrictions contained in our future debt instruments,
if any, which would intensify the risks discussed above.

The conditional exchange feature of the notes, if triggered,
may adversely affect our financial condition and operating results.

In the event the conditional exchange feature of
the notes is triggered, holders of notes will be entitled to exchange the notes at any time during specified periods at their option. If one or more holders elect to exchange their notes, unless we elect to satisfy its exchange obligation by
delivering solely the ADSs (other than cash in

lieu of any fractional ADS), we would be required to settle a portion or all of its exchange obligation through the payment of cash, which could adversely affect our liquidity. In addition, even
if holders do not elect to exchange their notes, we could be required under applicable accounting rules to reclassify all or a portion of the outstanding principal of the notes as a current rather than long-term liability, which would result in a
material reduction of our net working capital.

The change in control repurchase feature of the notes may delay or
prevent an otherwise beneficial takeover attempt of us.

The indenture governing the notes will require us to
repurchase the notes for cash upon the occurrence of a change in control of Amarin and, in certain circumstances, to increase the exchange rate for a holder that exchanges its notes in connection with a make-whole fundamental change. A takeover of
us may trigger the requirement that we purchase the notes and/or increase the exchange rate, which could make it more costly for a potential acquirer to engage in a combinatory transaction with us. Such additional costs may have the effect of
delaying or preventing a takeover of us that would otherwise be beneficial to investors.

We do not intend to pay cash
dividends on the ordinary shares in the foreseeable future.

We have never paid dividends on ordinary shares and do not
anticipate paying any cash dividends on the ordinary shares in the foreseeable future. Under English law, any payment of dividends would be subject to relevant legislation and our Articles of Association, which requires that all dividends must be
approved by our Board of Directors and, in some cases, our shareholders, and may only be paid from our distributable profits available for the purpose, determined on an unconsolidated basis.

The rights of our shareholders may differ from the rights typically offered to shareholders of a U.S. corporation.

We are incorporated under English law. The rights of holders of ordinary shares and, therefore, certain of the rights
of holders of ADSs, are governed by English law, including the provisions of the Companies Act 2006, and by our Articles of Association. These rights differ in certain respects from the rights of shareholders in typical U.S. corporations. The
principal differences include the following:



Under English law and our Articles of Association, each shareholder present at a meeting has only one vote unless demand is made for a vote on a poll,
in which case each holder gets one vote per share owned. Under U.S. law, each shareholder typically is entitled to one vote per share at all meetings.



Under English law, it is only on a poll that the number of shares determines the number of votes a holder may cast. You should be aware, however, that
the voting rights of ADSs are also governed by the provisions of a deposit agreement with our depositary bank.



Under English law, subject to certain exceptions and disapplications, each shareholder generally has preemptive rights to subscribe on a proportionate
basis to any issuance of ordinary shares or rights to subscribe for, or to convert securities into, ordinary shares for cash. Under U.S. law, shareholders generally do not have preemptive rights unless specifically granted in the certificate of
incorporation or otherwise.



Under English law and our Articles of Association, certain matters require the approval of 75% of the shareholders who vote (in person or by proxy) on
the relevant resolution (or on a poll shareholders representing 75% of the ordinary shares voting (in person or by proxy)), including amendments to the Articles of Association. This may make it more difficult for us to complete corporate
transactions deemed advisable by our board of directors. Under U.S. law, generally only majority shareholder approval is required to amend the certificate of incorporation or to approve other significant transactions.

In the United Kingdom, takeovers may be structured as takeover offers or as schemes of arrangement. Under English law, a bidder seeking to acquire us
by means of a takeover offer would need to make an offer for all of our outstanding ordinary shares/ADSs. If acceptances are not received for 90% or more of the ordinary shares/ADSs under the offer, under English law, the bidder cannot complete a
squeeze out to obtain 100% control of us. Accordingly, acceptances of 90% of our outstanding ordinary shares/ADSs will likely be a condition in any takeover offer to acquire us, not 50% as is more common in tender offers for corporations
organized under Delaware law. By contrast, a scheme of arrangement, the successful completion of which would result in a bidder obtaining 100% control of us, requires the approval of a majority of shareholders voting at the meeting and representing
75% of the ordinary shares voting for approval.



Under English law and our Articles of Association, shareholders and other persons whom we know or have reasonable cause to believe are, or have been,
interested in our shares may be required to disclose information regarding their interests in our shares upon our request, and the failure to provide the required information could result in the loss or restriction of rights attaching to the shares,
including prohibitions on certain transfers of the shares, withholding of dividends and loss of voting rights. Comparable provisions generally do not exist under U.S. law.



The quorum requirement for a shareholders meeting is a minimum of two shareholders entitled to vote at the meeting and present in person or by
proxy or, in the case of a shareholder which is a corporation, represented by a duly authorized officer. Under U.S. law, a majority of the shares eligible to vote must generally be present (in person or by proxy) at a shareholders meeting in
order to constitute a quorum. The minimum number of shares required for a quorum can be reduced pursuant to a provision in a companys certificate of incorporation or bylaws, but typically not below one-third of the shares entitled to vote at
the meeting.

U.S. shareholders may not be able to enforce civil liabilities against us.

We are incorporated under the laws of England and Wales, and our subsidiaries are incorporated in various
jurisdictions, including foreign jurisdictions. A number of the officers and directors of each of our subsidiaries are non-residents of the United States, and all or a substantial portion of the assets of such persons are located outside the United
States. As a result, it may not be possible for investors to affect service of process within the United States upon such persons or to enforce against them judgments obtained in U.S. courts predicated upon the civil liability provisions of the
federal securities laws of the United States. We have been advised by our English solicitors that there is doubt as to the enforceability in England in original actions, or in actions for enforcement of judgments of U.S. courts, of civil liabilities
to the extent predicated upon the federal securities laws of the United States.

U.S. holders of the ADSs or ordinary
shares may be subject to U.S. federal income taxation at ordinary income tax rates on undistributed earnings and profits.

There is a risk that we will be classified as a controlled foreign corporation, or CFC, for U.S. federal income tax purposes. If we are classified as a CFC, any ADS holder or shareholder that is a U.S.
person that owns directly, indirectly or by attribution, 10% or more of the voting power of our outstanding shares may be subject to U.S. income taxation at ordinary income tax rates on all or a portion of our undistributed earnings and profits
attributable to subpart F income. Such 10% holder may also be taxable at ordinary income tax rates on any gain realized on a sale of ordinary shares or ADS, to the extent of our current and accumulated earnings and profits attributable
to such shares. The CFC rules are complex and U.S. holders of the ordinary shares or ADSs are urged to consult their own tax advisors regarding the possible application of the CFC rules to them in their particular circumstances.

The following table lists the location, use and ownership interest of our principal properties as of February 20, 2016:

Location

Use

Ownership

Size (sq. ft.)

Dublin, Ireland

Offices

Leased

270

Bedminster, New Jersey, USA

Offices

Leased

21,231

Effective November 1, 2011, we leased 320 square feet of office space in Dublin, Ireland. The office
space was subsequently reduced to 270 square feet, effective November 1, 2013. The lease terminates on October 31, 2016 and may be renewed annually.

Effective July 1, 2011, we leased 9,747 square feet of office space in Bedminster, New Jersey. The lease, as amended, terminates on March 31, 2018, and may also be terminated with six months
prior notice. On December 6, 2011 we leased an additional 2,142 square feet of space in the same location. On December 15, 2012 and May 8, 2013, we leased an additional 2,601 and 10,883 square feet of space, respectively, in the same
location. In January 2014 and April 2014, we entered into separate transactions with the landlord of this property to vacate approximately 2,142 and 2,000 square feet of space in exchange for discounts on contractual future rent payments. In January
2015, we signed an agreement to sublease approximately 4,700 square feet of this property to a third party, effective April 1, 2015. Additionally, in June 2015, we executed an agreement to sublease approximately 2,500 square feet of this
property to a separate third party, effective June 16, 2015.

We believe our existing facilities are adequate for our
current needs and that additional space will be available in the future on commercially reasonable terms as needed.

Item 3.

Legal Proceedings

On May 7, 2015, we and a group of independent physicians filed a federal lawsuit to permit us to share truthful and non-misleading information, including, but not limited to, the ANCHOR trial
clinical data, with healthcare professionals in the United States about certain uses of Vascepa not included with approved FDA labeling of Vascepa and thus not permitted under the FDAs interpretation of applicable law. The lawsuit, captioned
Amarin Pharma, Inc., et al. v. Food & Drug Administration, et al. (1:15-cv-03588-PAE), was filed in the United States District Court for the Southern District of New York and seeks a judicial declaration based on several legal
theories. On August 7, 2015, the Court granted our request for preliminary relief in this litigation through a declaratory judgment that confirmed that we may engage in truthful and non-misleading speech promoting the off-label use of Vascepa,
i.e., to treat patients with persistently high triglycerides, and such speech may not form the basis of a misbranding action under the Federal Food and Drug Cosmetic Act. FDA did not appeal the Courts preliminary ruling prior to the
October 6, 2015 deadline for appeal. The underlying litigation has been stayed for settlement discussion and the parties are working toward settlement. We cannot predict the outcome of settlement negotiations or this litigation.

On May 28, 2015, the U.S. District Court for the District of Columbia granted our motion for summary judgment in our lawsuit against
the FDA, captioned Amarin Pharmaceuticals Ireland Ltd. v. Food & Drug Administration, et al., Civ. A. No. 14-0324 (D.D.C.). This lawsuit sought an order requiring FDA to recognize five-year, New Chemical Entity (NCE)
marketing exclusivity for Vascepa. The decision vacated the FDAs denial of our claim for such exclusivity and remanded to the FDA for proceedings consistent with the decision. FDA did not appeal the Courts decision prior to the
July 28, 2015 deadline for appeal. On July 22, 2015, Watson Laboratories Inc., the purported first Vascepa ANDA filer, sought to intervene and appeal the Courts decision. We and FDA opposed this intervention effort. The applicable
courts denied Watson the relief sought and appeal periods have expired. A new exclusivity determination by FDA has been pending since the May 28, 2015 District of Columbia court order setting aside FDAs denial of NCE exclusivity for
Vascepa. We believe Vascepa is entitled to NCE exclusivity, but cannot predict the outcome of FDAs determination.

In March, April, and May 2014, we received paragraph IV certification notices from six
companies contending to varying degrees that certain of our patents are invalid, unenforceable and/or will not be infringed by the manufacture, use, sale or offer for sale of a generic form of Vascepa as described in those companies
abbreviated new drug applications, or ANDAs. We commenced patent infringement lawsuits against each of these ANDA applicants. In each of the lawsuits, Amarin sought, among other remedies, an order enjoining the defendants from marketing generic
versions of Vascepa before the last to expire of the asserted patents expires in 2030. A summary of the lawsuits is below:



In April 2014, Amarin filed lawsuits against Apotex, Inc. and Apotex Corporation, or collectively, Apotex, in the U.S. District Court for the District
of New Jersey and the U.S. District Court for the Northern District of Illinois. The cases against Apotex are captioned Amarin Pharma, Inc. et al. v. Apotex, Inc. et al., Civ. A. No. 14-2550 (D.N.J) and Amarin Pharma, Inc. et al. v.
Apotex, Inc. et al., Civ. A. No. 14-2958 (N.D. Ill.). On August 27, 2014, Amarin voluntarily dismissed the Northern District of Illinois case against Apotex in favor of the New Jersey case, which concerns identical allegations of
patent infringement against Apotex.



In April 2014, Amarin filed lawsuits against Roxane Laboratories, Inc., or Roxane, in the U.S. District Court for the District of New Jersey and the
U.S. District Court for the Northern District of Ohio. The cases against Roxane are captioned Amarin Pharma, Inc. et al. v. Roxane Laboratories, Inc., Civ. A. No. 14-2551 (D.N.J) and Amarin Pharma, Inc. et al. v. Roxane Laboratories,
Inc., Civ. A. No. 14-901 (N.D. Ohio). On May 7, 2014, Amarin voluntarily dismissed the Northern District of Ohio case against Roxane in favor of the New Jersey case, which concerns identical allegations of patent infringement against
Roxane.



In April 2014, Amarin also filed a lawsuit against Dr. Reddys Laboratories, Inc. and Dr. Reddys Laboratories, Ltd., or
collectively, Dr. Reddys, in the U.S. District Court for the District of New Jersey. The case against Dr. Reddys is captioned Amarin Pharma, Inc. et al. v. Dr. Reddys Laboratories, Inc. et al., Civ. A.
No. 14-2760 (D.N.J.).



In May 2014, Amarin also filed a lawsuit against Watson Laboratories, Inc. and Actavis, Inc., or Watson, in the U.S. District Court for the District of
New Jersey. One of our directors, Patrick J. OSullivan, is also a director of Actavis, Inc.. The case against Watson is captioned Amarin Pharma, Inc. et al. v. Watson Laboratories, Inc. et al., Civ. A. No. 14-3259 (D.N.J). On
July 17, 2014, Amarin agreed to dismiss Actavis, Inc. from the case, and the Court accordingly dismissed Actavis, Inc. on November 3, 2014.



In June 2014, Amarin also filed a case against Teva Pharmaceuticals USA, Inc., or Teva, in the U.S. District Court for the District of New Jersey. The
case against Teva is captioned Amarin Pharma, Inc. et al. v. Teva Pharmaceuticals USA, Inc., Civ. A. No. 14-3558 (D.N.J.).



In June 2014, Amarin also filed a lawsuit against Andrx Labs, LLC, Andrx Corporation, and Actavis plc, or collectively, Andrx, in the U.S. District
Court for the District of New Jersey. The case against Andrx is captioned Amarin Pharma, Inc. et al v. Andrx Labs, LLC et. al., Civ. A. No. 14-3924 (D.N.J.).

As a result of the 30-month stay associated with the filing of these lawsuits under the Hatch-Waxman Act, the FDA cannot grant final
approval to any ANDA before September 2016, unless there is an earlier court decision holding that the subject patents are not infringed and/or are invalid.

Based on the May 28, 2015 U.S. District Court for the District of Columbia order granting our motion for summary judgment in the NCE litigation, on June 26, 2015, the parties to the related ANDA
litigation identified above agreed to a full stay of proceedings. FDA subsequently notified the ANDA filers that FDA had changed the status of their ANDAs to submitted, but no longer accepted. In rescinding acceptance of the ANDAs, we believed the
statutory basis for the ANDA-related patent litigation (accepted ANDAs) no longer existed. Thus, on July 24, 2015, we moved to dismiss the pending patent infringement lawsuits against each of the Vascepa ANDA applicants in the U.S. District
Court for the District of New Jersey. On January 22, 2016, the U.S. District

Court for the District of New Jersey granted Amarins motion to dismiss all patent infringement litigation related to the 2014 acceptance by the FDA of ANDAs to Vascepa. With this dismissal,
there is no pending patent litigation related to Vascepa. A notice of appeal of the courts dismissal was filed by one ANDA filer in this case and we intend to continue to litigate vigorously in support of the courts dismissal. We cannot
predict the outcome of this litigation.

A new exclusivity determination by FDA has been pending since the May 28, 2015
District of Columbia court order setting aside FDAs denial of NCE exclusivity for Vascepa. We believe Vascepa is entitled to NCE exclusivity, but cannot predict the outcome of FDAs determination. The legal process can also be costly and
time-consuming. We plan to defend the exclusivity of Vascepa through patent litigation after notification that FDA has accepted an ANDA application related to Vascepa. Assuming an NCE exclusivity determination from the FDA or no exclusivity
determination, we expect notification of new ANDA submissions no sooner than in late July 2016, after the expiration of four years from the 2012 approval of Vascepa.

On June 29, 2015, the U.S. District Court for the District of New Jersey granted our motion to dismiss the putative consolidated class action lawsuit captioned In re Amarin Corporation plc,
Securities Litigation, No. 3:13-cv-06663 (D.N.J. Nov. 1, 2013). The class action was dismissed without prejudice with leave for plaintiffs to file an amended complaint. The lawsuit sought unspecified monetary damages and attorneys
fees and costs alleging that we and certain of our current and former officers and directors made misstatements and omissions regarding the FDAs willingness to approve Vascepas ANCHOR indication and related contributing factors and the
potential relevance of data from the ongoing REDUCE-IT trial to that potential approval. On July 29, 2015, plaintiffs filed an amended complaint alleging facts similar to those in the original complaint. Like the first complaint, the amended
complaint seeks unspecified monetary damages and attorneys fees and costs. We believe we have valid defenses and will continue to vigorously defend against this lawsuit, but cannot predict the outcome. We have insurance coverage that is
anticipated to cover any significant loss exposure that may arise from this action.

In addition to the above, in the ordinary
course of business, we are from time to time involved in lawsuits, claims, investigations, proceedings, and threats of litigation relating to intellectual property, commercial arrangements and other matters.

The
following table sets forth the high and low prices for our ADSs in each of the quarters over the past two fiscal years, as quoted on the NASDAQ Global Market.

Common Stock Price

Fiscal 2015

Fiscal 2014

High

Low

High

Low

First Quarter

$

3.33

$

0.98

$

2.75

$

1.60

Second Quarter

$

2.80

$

1.82

$

1.98

$

1.28

Third Quarter

$

2.59

$

1.58

$

2.09

$

1.07

Fourth Quarter

$

2.19

$

1.79

$

1.38

$

0.78

Shareholders

As of January 31, 2016, there were approximately 385 holders of record of our ordinary shares. Because many ordinary shares are held by broker nominees, we are unable to estimate the total number of
shareholders represented by these record holders. Our depositary, Citibank, N.A., constitutes a single record holder of our ordinary shares.

Dividends

We have never
paid dividends on common shares and do not anticipate paying any cash dividends on the common shares in the foreseeable future. Under English law, any payment of dividends would be subject to relevant legislation and our Articles of Association,
which requires that all dividends must be approved by our Board of Directors and, in some cases, our stockholders, and may only be paid from our distributable profits available for the purpose, determined on an unconsolidated basis.

Under our Purchase and Sale Agreement with BioPharma Secured Debt Fund II Holdings Cayman LP, or BioPharma, we are restricted from paying
a dividend on our common shares, unless we have cash and cash equivalents in excess of a specified amount after such payment.

The following performance graph and related information shall not be deemed soliciting material or to be filed
with the Securities and Exchange Commission, nor shall such information be incorporated by reference into any future filing under the Securities Act of 1933 or Securities Exchange Act of 1934, each as amended, except to the extent that we
specifically incorporate it by reference into such filing.

The following graph compares the cumulative 5-year return
provided to stockholders of Amarins ADSs relative to the cumulative total returns of the NASDAQ Composite Index and the NASDAQ Biotechnology Index. We believe these indices are the most appropriate indices against which the total shareholder
return of Amarin should be measured. The NASDAQ Biotechnology Index has been selected because it is an index of U.S. quoted biotechnology and pharmaceutical companies. An investment of $100 (with reinvestment of all dividends) is assumed to have
been made in our ADSs and in each of the indexes on January 1, 2011 and its relative performance is tracked through December 31, 2015.

The following performance graph and related information shall not be deemed soliciting material or to be filed
with the Securities and Exchange Commission, nor shall such information be incorporated by reference into any future filing under the Securities Act of 1933 or Securities Exchange Act of 1934, each as amended, except to the extent that we
specifically incorporate it by reference into such filing.

The following graph compares the cumulative 1-year return
provided to stockholders of Amarins ADSs relative to the cumulative total returns of the NASDAQ Composite Index and the NASDAQ Biotechnology Index. We believe these indices are the most appropriate indices against which the total shareholder
return of Amarin should be measured. The NASDAQ Biotechnology Index has been selected because it is an index of U.S. quoted biotechnology and pharmaceutical companies. An investment of $100 (with reinvestment of all dividends) is assumed to have
been made in our ADSs and in each of the indexes on January 1, 2015 and its relative performance is tracked through December 31, 2015.

Company/Market/Peer Company

3/31/2015

6/30/2015

9/30/2015

12/31/2015

Amarin Corporation PLC

$

238.78

$

251.02

$

196.94

$

192.86

NASDAQ Composite Index

$

103.79

$

105.90

$

98.39

$

106.96

NASDAQ Biotechnology Index

$

113.27

$

121.79

$

99.96

$

111.77

Information about Our Equity Compensation Plans

Information regarding our equity compensation plans is incorporated by reference in Item 12 of Part III of this annual report on Form
10-K.

Unregistered Sales of Equity Securities and Use of Proceeds

Issuer Purchases of Equity Securities

Shares purchased in the fourth
quarter of 2015 are as follows:

Period

Total Number
ofShares Purchased (1)

Average PricePaid
per Share

October 1  31, 2015

2,349

$

2.05

November 1  30, 2015





December 1  31, 2015

20,082

1.89

Total

22,431

$

1.91

(1)

Represents shares withheld to satisfy tax withholding amounts due from employees related to the receipt of stock which resulted from the exercise or vesting of equity
awards.

If you are not resident or ordinarily resident in the United
Kingdom, or UK, for UK tax purposes, you will not be liable for UK tax on capital gains realized or accrued on the sale or other disposition of common shares or ADSs unless the common shares or ADSs are held in connection with your trade carried on
in the UK through a branch or agency and the common shares or ADSs are or have been used, held or acquired for the purposes of such trade or such branch or agency.

An individual holder of common shares or ADSs who ceases to be resident or ordinarily resident in the UK for UK tax purposes for a period of less than 5 years and who disposes of common shares or ADSs
during that period may also be liable on returning to the UK for UK capital gains tax despite the fact that the individual may not be resident or ordinarily resident in the UK at the time of the disposal.

Inheritance Tax

If you
are an individual domiciled in the United States and are not a national of the UK for the purposes of the Inheritance and Gift Tax Treaty 1978 between the United States and the UK, any common shares or ADSs beneficially owned by you will not
generally be subject to UK inheritance tax on your death or on a gift made by you during your lifetime, provided that any applicable United States federal gift or estate tax liability is paid, except where the common share or ADS is part of the
business property of your UK permanent establishment.

Where the common shares or ADSs have been placed in trust by a settlor
who, at the time of the settlement, was domiciled in the United States and not a national of the UK, the common shares or ADSs will not generally be subject to UK inheritance tax.

Stamp Duty and Stamp Duty Reserve Tax

Transfer of ADSs

No UK stamp duty will be payable on an instrument transferring an ADS or on a written agreement to transfer an ADS provided that the
instrument of transfer or the agreement to transfer is executed and remains at all times outside the UK. Where these conditions are not met, the transfer of, or agreement to transfer, an ADS could, depending on the circumstances, attract a charge to
ad valorem stamp duty at the rate of 0.5% of the value of the consideration.

No stamp duty reserve tax will be payable in
respect of an agreement to transfer an ADS, whether made in or outside the UK.

Issue and Transfer of Common Shares

The issue of common shares by Amarin will not give rise to a charge to UK stamp duty or stamp duty reserve tax.

Transfers of common shares, as opposed to ADSs, will attract ad valorem stamp duty at the rate of 0.5% of the amount or value of the
consideration. A charge to stamp duty reserve tax, at the rate of 0.5% of the amount or value of the consideration, will arise on an agreement to transfer common shares. The stamp duty reserve tax is payable on the seventh day of the month following
the month in which the charge arises. Where an instrument of transfer is executed and duly stamped before the expiry of a period of six years beginning with the date of that agreement, any stamp duty reserve tax that has not been paid ceases to be
payable.

The selected financial data set forth below as of and for the years ended December 31, 2015, 2014, 2013, 2012, and 2011 have been derived from the audited consolidated financial statements of Amarin.
This data should be read in conjunction with our audited consolidated financial statements and related notes which are included elsewhere in this Annual Report on Form 10-K, and Managements Discussion and Analysis of Financial Condition
and Results of Operations included in Item 7 below. Historical results are not necessarily indicative of operating results to be expected in the future.

Years Ended December 31,

2015

2014

2013

2012

2011

(In thousands, except per share amounts)

Consolidated Statements of Operations Data:

Product revenue, net

$

80,987

$

54,202

$

26,351

$



$



Licensing revenue

769









Total revenue, net

81,756

54,202

26,351





Less: Cost of goods sold

27,875

20,485

11,912





Gross margin

53,881

33,717

14,439





Operating expenses:

Selling, general and administrative (1)

101,041

79,346

123,795

57,794

22,559

Research and development

51,062

50,326

72,750

58,956

21,602

Total operating expenses

152,103

129,672

196,545

116,750

44,161

Operating loss

(98,222

)

(95,955

)

(182,106

)

(116,750

)

(44,161

)

(Loss) gain on change in fair value of derivativeliabilities (2)

(1,106

)

13,472

47,710

(35,344

)

(22,669

)

Gain on extinguishment of debt

1,314

38,034







Interest expense

(20,180

)

(18,575

)

(34,179

)

(18,091

)

(1

)

Interest income

132

96

343

544

231

Other (expense) income, net

(228

)

3,727

(1,189

)

(427

)

(10

)

Loss from operations before taxes

(118,290

)

(59,201

)

(169,421

)

(170,068

)

(66,610

)

Benefit from (provision for) income taxes

3,086

2,837

3,194

(9,116

)

(2,516

)

Net loss

(115,204

)

(56,364

)

(166,227

)

(179,184

)

(69,126

)

Preferred stock purchase option

(868

)









Preferred stock beneficial conversion features

(32,987

)









Net loss applicable to common shareholders

$

(149,059

)

$

(56,364

)

$

(166,227

)

$

(179,184

)

$

(69,126

)

Loss per share:

Basic

$

(0.83

)

$

(0.32

)

$

(1.03

)

$

(1.24

)

$

(0.53

)

Diluted

$

(0.83

)

$

(0.36

)

$

(1.28

)

$

(1.24

)

$

(0.53

)

Weighted average shares:

Basic

180,654

173,719

161,022

144,017

130,247

Diluted

180,654

173,824

167,070

144,017

130,247

As of December 31,

2015

2014

2013

2012

2011

(In thousands)

Consolidated Balance Sheet Data:

Cash and cash equivalents

$

106,961

$

119,539

$

191,514

$

260,242

$

116,602

Total assets

173,462

171,107

252,476

310,855

126,379

Long-term liabilities

251,930

219,249

248,792

289,650

123,889

Stockholders deficit

(129,191

)

(88,448

)

(33,856

)

(3,997

)

(5,962

)

(1)

Includes non-cash warrant-related compensation expense reflecting the change in the fair value of the warrant derivative liability associated with warrants issued in
October 2009 to former officers of Amarin. See further discussion in Notes 2 and 7 of the Notes to the Consolidated Financial Statements.

(2)

Includes non-cash charges resulting from changes in the fair value of derivative liabilities. See further discussion in Notes 2 and 7 of the Notes to the Consolidated
Financial Statements.

Managements Discussion and Analysis of Financial Condition and Results of Operations

This Annual Report on Form 10-K contains forward-looking statements concerning future events and performance of the Company. When used
in this report, the words may, would, should, could, expects, aims, plans, anticipates, believes, estimates,
predicts, projects, potential, or continue or the negative of these terms or other comparable terminology are included to identify forward-looking statements. These statements include but are not
limited to statements regarding the commercial success of Vascepa and factors that can affect such success; interpretation of court decisions; expectation on determinations and policy positions of the United States Food and Drug Administration, or
FDA; the expected timing of enrollment, interim results and final results of our REDUCE-IT study; the safety and efficacy of our product and product candidates; expectation regarding the potential for Vascepa to be partnered, developed and
commercialized outside of the United States; expectation on the scope and strength of our intellectual property protection and the likelihood of securing additional patent protection; estimates of the potential markets for our product candidates;
estimates of the capacity of manufacturing and other facilities to support our products; our operating and growth strategies; our industry; our projected cash needs, liquidity and capital resources; and our expected future revenues, operations and
expenditures. These forward-looking statements are based on our current expectations and assumptions and many factors could cause our actual results to differ materially from those indicated in these forward-looking statements. You should review
carefully the factors identified in this report in Item 1A, Risk Factors. We disclaim any intent to update or announce revisions to any forward-looking statements to reflect actual events or developments, except as required by law.
Except as otherwise indicated herein, all dates referred to in this report represent periods or dates fixed with reference to our fiscal year ended December 31. 2015.

Overview

We are a biopharmaceutical company with expertise in lipid
science focused on the commercialization and development of therapeutics to improve cardiovascular health.

Our lead product, Vascepa® (icosapent ethyl) capsules, is approved by the U.S. Food and Drug Administration, or FDA, for use as an adjunct to diet to reduce triglyceride levels in adult
patients with severe (TG ³500 mg/dL) hypertriglyceridemia. This FDA-approved indication for Vascepa, known as the MARINE indication, is based primarily on the successful results from the MARINE study of
Vascepa in this approved patient population. In considering this approval, FDA also reviewed our successful study of Vascepa in patients with high triglyceride levels (TG ³200 mg/dL and <500 mg/dL) who
are also on statin therapy for elevated low-density lipoprotein cholesterol, or LDL-C, levels which condition we refer to as mixed dyslipidemia. This study is known as the ANCHOR study. Safety data from both the MARINE and ANCHOR studies are
reflected in FDA-approved labeling for Vascepa. In January 2013, we began selling and marketing Vascepa in the United States based on the FDA-approved MARINE indication. In August 2015, we also began marketing Vascepa in the United States for the
treatment of patients studied in the ANCHOR study based on the federal court declaration described below. Vascepa is available in the United States by prescription only.

We sell Vascepa principally to a limited number of major wholesalers, as well as selected regional wholesalers and specialty pharmacy providers, or collectively, its Distributors, that in turn resell
Vascepa to retail pharmacies for subsequent resale to patients and healthcare providers. We market Vascepa in the United States through our sales force of approximately 150 sales professionals, including sales representatives and their managers. In
March 2014, we entered into a co-promotion agreement in the United States with Kowa Pharmaceuticals America, Inc. under which approximately 250 Kowa Pharmaceuticals America, Inc. sales representatives began to devote a substantial portion of their
time to promoting Vascepa starting in May 2014.

In February 2015, we announced an exclusive agreement with Eddingpharm (Asia)
Macao Commercial Offshore Limited, or Eddingpharm, to develop and commercialize Vascepa capsules in Mainland China, Hong Kong, Macau and Taiwan, or the China Territory. We are also assessing other partnership opportunities for licensing Vascepa in
other territories outside of the United States.

Triglycerides are fats in the blood. Hypertriglyceridemia refers to a condition in which
patients have high levels of triglycerides in the bloodstream. It is estimated that over 70 million adults in the United States have elevated triglyceride levels (TG >150 mg/dL), approximately 40 million adults in the United
States have high triglyceride levels (TG >200 mg/dL), and approximately 4.0 million people in the United States have severely high triglyceride levels (TG >500 mg/dL), commonly known as very high triglyceride levels. Many
patients with high triglyceride levels also have diabetes and other lipid level abnormalities such as high cholesterol. The patient condition of having more than one lipid level abnormality is referred to as mixed dyslipidemia. According to The
American Heart Association Scientific Statement on Triglycerides and Cardiovascular Disease (2011), triglycerides provide important information as a marker associated with the risk for heart disease and stroke, especially when an individual also
has low high-density lipoprotein cholesterol, or HDL-C (often referred to as good cholesterol), and elevated levels of LDL-C (often referred to as bad cholesterol). Guidelines for the management of very high triglyceride
levels suggest that reducing triglyceride levels is the primary goal in patients to reduce the risk of acute pancreatitis. The effect of Vascepa on cardiovascular mortality and morbidity, or the risk for pancreatitis, in patients with
hypertriglyceridemia has not been determined.

We are currently focused on completing the ongoing REDUCE-IT (Reduction of
Cardiovascular Events with EPAIntervention Trial) cardiovascular outcomes study of Vascepa, which we started in December 2011. REDUCE-IT, a multinational, prospective, randomized, double-blind, placebo-controlled study, is the first
prospective cardiovascular outcomes study of any drug in a population of patients who, despite stable statin therapy, have elevated triglyceride levels. Based on the results of REDUCE-IT, we plan to seek additional indicated uses for Vascepa. In
REDUCE-IT, cardiovascular event rates for patients on stable statin therapy plus four grams per day of Vascepa will be compared to cardiovascular event rates for patients on stable statin therapy plus placebo. The REDUCE-IT study is designed to be
completed after reaching 1,612 aggregate cardiovascular events. Based on projected event rates, we estimate the onset of the target aggregate number of cardiovascular events to be reached in or about 2017 with study results then expected to be
available and published in 2018. An interim review of the efficacy and safety results of the trial is scheduled to occur upon reaching 60% of the target aggregate number of cardiovascular events. We currently expect this interim review by the
independent data monitoring committee (DMC) to occur during 2016 and it is our expectation that the trial will run to completion. In addition, we have instructed the DMC to not recommend stopping the study early based only upon achieving statistical
significance for the primary endpoint, but to ensure that statistical significance is also achieved for certain subpopulations before recommending that the study be stopped early for overwhelming efficacy. The DMC has been more frequently examining
interim reviews of the safety data from the study. Following each of these reviews, the DMC has communicated to us that we should continue the study as planned. We remain blinded to all data from the study. Over 99% of the approximately 8,000
patients targeted for enrollment in the REDUCE-IT study have been enrolled and we have pre-notified all clinical sites in the REDUCE-IT study of our intention to cease patient enrollment soon. Since patient enrollment commenced in 2011,
approximately 20,000 patient years of study experience have been accumulated in REDUCE-IT.

In the successful Phase 3 MARINE
and ANCHOR clinical trials, Vascepa was studied at a daily dose of 2 grams and 4 grams. We sought approval of Vascepa at the more efficacious 4-gram dose for use in each patient population. These trials demonstrated favorable results in their
respective patient populations, particularly with the 4-gram dose of Vascepa, in reducing triglyceride levels without increasing LDL-C levels in the MARINE trial and with a statistically significant decrease in LDL-C levels in the ANCHOR trial, in
each case, relative to placebo. These trials also showed favorable results, particularly with the 4-gram dose of Vascepa, in other important lipid and inflammation biomarkers, including apolipoprotein B (apo B), non-high-density lipoprotein
cholesterol (non-HDL-C), total-cholesterol (TC), very low-density lipoprotein cholesterol (VLDL-C), lipoprotein-associated phospholipase A2 (Lp-PLA2), and high sensitivity C-reactive protein (hs-CRP). In these trials, the most commonly reported
adverse reaction (incidence >2% and greater than placebo) in Vascepa-treated patients was arthralgia (joint pain) (2.3% for Vascepa vs. 1.0% for placebo).

In April 2015, we received a Complete Response Letter, or CRL, from the FDA in response to our supplemental new drug application, or sNDA, that sought approval of Vascepa for use in patients with mixed

dyslipidemia, based on the successful ANCHOR study. The CRL followed an October 2013 rescission by the FDA of a special protocol assessment, or SPA, agreement and three failed attempts by us to
appeal that rescission at FDA. The FDA has acknowledged the success of the ANCHOR study, which met all primary and secondary endpoints. However, FDA determined that there were insufficient data to conclude that drug-induced changes in serum
triglycerides could be recognized by the FDA as a valid surrogate for reducing cardiovascular risk in the ANCHOR population for the purpose of regulatory approval of a drug targeted at a triglyceride-lowering indication in this population. The FDA
has acknowledged that the standard of proof required by the FDA for approval of a new drug indication is higher than that generally used to inform patient treatment guidelines and that used by physicians in clinical practice. The FDA did not
determine that the drug-induced effects of Vascepa, which go beyond triglyceride-lowering, would not actually reduce cardiovascular risk in this population and the FDA has encouraged us to complete the REDUCE-IT outcomes study. Based on our
communications with the FDA, we expect that final positive results from the REDUCE-IT outcomes study will be required for label expansion for Vascepa.

In May 2015, we and a group of independent physicians filed a lawsuit in federal court to permit us to promote to healthcare professionals the use of Vascepa in patients with mixed dyslipidemia so long as
the promotion is truthful and non-misleading. This use reflects recognized medical practice but is not covered by current FDA-approved labeling for the drug and has thus been considered by FDA to be illegal off-label promotion. In August 2015, we
were granted preliminary relief in the form of a declaratory judgment in this lawsuit. The court declaration permits us to promote to healthcare professionals the FDA-reviewed and agreed effects of Vascepa demonstrated in the ANCHOR clinical trial
and presentation of the current state of scientific research related to the potential of Vascepa to reduce the risk of cardiovascular disease including through use of peer-reviewed scientific publications of available data. The FDA did not appeal
the courts ruling prior to the October 6, 2015 deadline. The underlying litigation has been stayed for settlement discussion and the parties are working toward settlement. In August 2015, we began to promote Vascepa to healthcare
professionals as permitted by this court declaration. While we are permitted to more broadly promote Vascepa based on this court declaration, the FDA-approved labeling for Vascepa did not change based on the court declaration, and neither government
nor other third-party coverage or reimbursement to pay for the off-label use of Vascepa promoted under the court declaration was required.

CommercializationUnited States

We commenced the commercial launch of
Vascepa in the United States in January 2013. We commenced sales and shipments of Vascepa at that time to our network of U.S.-based wholesalers. We now market Vascepa in the United States through our sales force of approximately 150 sales
professionals, including sales representatives and their managers. Commencing in May 2014, in addition to promotion by our sales representatives, approximately 250 Kowa Pharmaceuticals America, Inc. sales representatives began promoting Vascepa. We
also employ various marketing personnel to support our commercialization of Vascepa.

Under our co-promotion agreement with
Kowa Pharmaceuticals America, Inc., both parties have agreed to use commercially reasonable efforts to promote, detail and optimize sales of Vascepa in the United States and have agreed to specific performance requirements detailed in the related
agreement. The performance requirements include a negotiated minimum number of sales details to be delivered by each party in the first and second position, the use of a negotiated number of minimum sales representatives from each party, including
no less than 250 Kowa Pharmaceuticals America, Inc. sales representatives and the achievement of minimum levels of Vascepa revenue in 2015 and beyond. First position refers to when a sales representatives primary purpose in detailing is
related to Vascepa, while second position refers to when a sales representatives primary purpose in detailing is to promote another product, but they also devote time in the same sales call to promote Vascepa. Kowa Pharmaceuticals America,
Inc. has also agreed to continue to bear the costs incurred for its sales force associated with the commercialization of Vascepa and to pay for certain incremental costs associated with the use of its sales force, such as sample costs and costs for
promotional and marketing materials. We will continue to recognize all revenue from sales of Vascepa. In exchange for Kowa Pharmaceuticals America, Inc.s

co-promotional services, Kowa Pharmaceuticals America, Inc. is entitled to a quarterly co-promotion fee based on a percentage of aggregate Vascepa gross
margins that increases during the term. The percentage of aggregate Vascepa gross margins earned by Kowa Pharmaceuticals America, Inc. increased from the high single digits in 2014, to fifteen percent (15%) in 2015, and is scheduled to increase
to the low twenty percent levels in 2018, subject to certain adjustments. The term of this co-promotion agreement expires on December 31, 2018, following which Kowa Pharmaceuticals America, Inc. will be entitled to earn tail royalties equal to
declining fractions of the co-promotion fee in effect prior to such expiration for periods ranging from one to three years following such expiration.

Based on monthly compilations of data provided by a third party, Symphony Health Solutions, the estimated number of normalized total Vascepa prescriptions for the three months ended December 31, 2015
was approximately 192,000 compared to 169,000, 148,000, 130,000, and 126,000 in the three months ended September 30, 2015, June 30, 2015, March 31, 2015, and December 31, 2014, respectively. According to data from
another third party, IMS Health, the estimated number of normalized total Vascepa prescriptions for the three months ended December 31, 2015 was approximately 203,000 compared to 176,000, 157,000, 137,000, and 131,000 in the three months ended
September 30, 2015, June 30, 2015, March 31, 2015, and December 31, 2014, respectively. Normalized total prescriptions represent the estimated total number of Vascepa prescriptions shipped to patients, calculated on a
normalized basis (i.e., total capsules shipped divided by 120 capsules, or one months supply). The data reported above is based on information made available to us from third-party resources and may be subject to adjustment and may overstate
or understate actual prescriptions. Timing of shipments to wholesalers, as used for revenue recognition purposes, and timing of prescriptions as estimated by these third parties may differ from period to period. Although we believe these data are
prepared on a period-to-period basis in a manner that is generally consistent and that such results are generally indicative of current prescription trends, these data are based on estimates and should not be relied upon as definitive. While we
expect to be able to grow Vascepa revenues over time, no such guidance should be inferred from the operating metrics described above. We also anticipate that such sales growth may be inconsistent from period to period. We believe that investors
should view the above-referenced operating metrics with caution, as data for this limited period may not be representative of a trend consistent with the results presented or otherwise predictive of future results. Seasonal fluctuations in
pharmaceutical sales, for example, may affect future prescription trends of Vascepa, as could changes in prescriber sentiment and other factors. We believe investors should consider our results over several quarters, or longer, before making an
assessment about potential future performance.

The commercialization of pharmaceutical products is a complex undertaking, and
our ability to effectively and profitably commercialize Vascepa will depend in part on our ability to generate market demand for Vascepa through education, marketing and sales activities, our ability to achieve market acceptance of Vascepa, our
ability to generate product revenue and our ability to receive adequate levels of reimbursement from third-party payers. See Risk FactorsRisks Related to the Commercialization and Development of Vascepa.

In August 2015, we and our co-promotion partner began communicating ANCHOR clinical trial data to targeted healthcare professionals. Such
qualified communications are being made pursuant to the August 7, 2015 federal district court declaration allowing truthful and non-misleading promotion of the FDA-reviewed and agreed effects of Vascepa demonstrated in the ANCHOR clinical trial
and presentation of the current state of scientific research related to the potential of Vascepa to reduce the risk of cardiovascular disease including through use of peer-reviewed scientific publications of available data.

CommercializationOutside the United States

In February 2015, we announced an exclusive agreement with Eddingpharm to develop and commercialize Vascepa capsules in what we refer to as the China Territory, consisting of the territories of Mainland
China, Hong Kong, Macau and Taiwan, for uses that are currently commercialized and under development by us in the United States based on the MARINE, ANCHOR and ongoing REDUCE-IT clinical trials of Vascepa.

Under the agreement, Eddingpharm is responsible for development and commercialization
activities in the China Territory and associated expenses. We will provide development assistance and be responsible for supplying the product. Terms of the agreement include up-front and milestone payments to us of up to $169.0 million, including a
non-refundable $15.0 million up-front payment received at closing, and development, regulatory and sales-based milestone payments of up to an additional $154.0 million. Eddingpharm will also pay us tiered double-digit percentage royalties on net
sales of Vascepa in the China Territory escalating to the high teens. We will supply finished product to Eddingpharm under negotiated terms.

We continue to assess other partnership opportunities for licensing Vascepa in other territories outside of the United States.

Research and Development

REDUCE-IT is the first prospective cardiovascular
outcomes study of any drug in a population of patients who, despite stable statin therapy, have elevated triglyceride levels. REDUCE-IT is a multinational, prospective, randomized, double-blind, placebo-controlled study designed to assess the
cumulative effect on the rate of cardiovascular events for patients treated with Vascepa as an add-on to statin therapy compared to the corresponding rate of cardiovascular events for patients treated with placebo on top of statin therapy. Based on
the results of REDUCE-IT, we may seek additional indications for Vascepa beyond the indications studied in the ANCHOR or MARINE trials.

REDUCE-IT is designed to enroll approximately 8,000 patients and enrollment is over 99% complete. We have pre-notified all clinical trial sites in the REDUCE-IT study of our intention to cease further
patient enrollment soon. Since patient enrollment commenced in 2011, approximately 20,000 patient years of study experience have been accumulated in REDUCE-IT.

Completion of the REDUCE-IT study is designed to occur after reaching an aggregate number of cardiovascular events. Based on projected event rates, we estimate the onset of the target aggregate number of
cardiovascular events to be reached in or about 2017 with study results then expected to be available in 2018. An interim review of the efficacy and safety results of the trial is scheduled to occur upon reaching 60% of the target aggregate number
of cardiovascular events. We currently expect this interim review by the independent data monitoring committee, or DMC, to occur during 2016. As is typical, the statistical threshold for defining overwhelming efficacy on the primary endpoint at the
interim analysis is considerably higher than the threshold for defining statistical significance at the end of the study and it is our expectation that the trial will run to completion. In addition, we have instructed the DMC to not recommend
stopping the study early based only upon achieving statistical significance for the primary endpoint, but to ensure that statistical significance is also achieved for certain subpopulations before recommending that the study be stopped early for
overwhelming efficacy. Amarin remains blinded to all data from the study. Unless overwhelming efficacy and safety is declared by the DMC at the interim look or the study is halted due to a patient safety concern, Amarin personnel will remain blinded
to the efficacy and safety data from the REDUCE-IT study until the study is complete. The DMC has periodically reviewed unblinded safety data since initiation of the REDUCE-IT study in 2011 and, after each such meeting to date, has recommended that
the study be continued as planned. The pre-specified interim review at 60% of the target aggregate number of cardiovascular events will involve a look by the DMC in closed session at all efficacy and safety data available from the REDUCE-IT study at
that time. Interim looks by independent DMCs are common in large, long-term outcomes studies. By design, it is most common for cardiovascular outcomes studies not to be stopped upon an interim look.

levels correlates with reduced cardiovascular risk. Our scientific rationale for the REDUCE-IT study is also supported by research on the putative cardioprotective effects of EPA as presented in
scientific literature. It is possible that the effects of EPA may be due not to a single mode of action, such as triglyceride lowering, but rather to multiple mechanisms working together. Studies in the scientific literature explore potentially
beneficial effects of EPA on multiple atherosclerosis processes, including endothelial function, oxidative stress, foam cell formation, inflammation/cytokines, plaque formation/progression, platelet aggregation, thrombus formation, and plaque
rupture. The REDUCE-IT study is needed to determine the clinical benefit, if any, of EPA therapy in statin-treated patients with elevated triglyceride levels.

Commercial Supply

Prior to 2015, all of our active pharmaceutical
ingredient, or API, that has been utilized in product sold was manufactured by two suppliers: Nisshin Pharma, Inc., or Nisshin, and Chemport, Inc., or Chemport. A significant portion of such API was purchased from Nisshin at a price that is higher
than expected future average API costs. During 2015, we began purchasing API from a third supplier, Finorga SAS, or Novasep. The amount of supply we seek to purchase in future periods will depend on the level of growth of Vascepa revenues and
minimum purchase commitments with certain suppliers. We continue efforts to expand, diversify and enhance our commercial supply chain.

Financial Position

We believe that our cash and cash equivalents balance
of $107.0 million as of December 31, 2015 is sufficient to fund our projected operations for at least the next twelve months. Depending on the level of cash generated from operations, additional capital may be required to sustain operations.

Financial Operations Overview

Product Revenues, net. All of our revenue is derived from product sales of Vascepa, net of allowances, discounts, incentives, rebates, chargebacks and returns. We sell product to a limited number
of major wholesalers, as well as selected regional wholesalers and specialty pharmacy providers, or collectively, our Distributors, who resell the product to retail pharmacies for purposes of their reselling the product to fill patient
prescriptions. We commenced our commercial launch in the United States in January 2013. In accordance with GAAP, until we had the ability to reliably estimate returns of Vascepa from our Distributors, revenue was recognized based on the resale of
Vascepa for the purposes of filling patient prescriptions, and not based on our sales to such Distributors. During the three months ended March 31, 2014, we concluded that we had developed sufficient history such that we can reliably estimate
returns and as a result, began to recognize revenue based on sales to our Distributors. Through December 31, 2015, product returns were de minimis.

Licensing revenue. Licensing revenue currently consists of revenue attributable to the receipt of an up-front, non-refundable payment related to a Vascepa license agreement in China, which is being
recognized over the estimated period in which we are required to provide regulatory and development support and clinical and commercial supply pursuant to the agreement, which is currently anticipated to be a period of approximately 16 years.

Cost of Goods Sold. Cost of goods sold includes the cost of API for Vascepa on which revenue was recognized during the
period, as well as the associated costs for encapsulation, packaging, shipment, supply management, insurance and quality assurance. The cost of the API included in cost of goods sold reflects the average cost method of inventory valuation and
relief. This average cost reflects the actual purchase price of Vascepa API.

Selling, General and Administrative
Expense. Selling, general and administrative expense consists primarily of salaries and other related costs, including stock-based compensation expense, for personnel in our sales,

marketing, executive, business development, finance and information technology functions, as well as co-promotion fees payable to Kowa Pharmaceuticals America, Inc. Other costs primarily include
facility costs and professional fees for accounting, consulting and legal services.

Research and Development Expense.
Research and development expense consists primarily of fees paid to professional service providers in conjunction with independent monitoring of our clinical trials and acquiring and evaluating data in conjunction with our clinical trials, fees paid
to independent researchers, costs of qualifying contract manufacturers, services expenses incurred in developing and testing products and product candidates, salaries and related expenses for personnel, including stock-based compensation expense,
costs of materials, depreciation, rent, utilities and other facilities costs. In addition, research and development expenses include the cost to support current development efforts, including patent costs and milestone payments. We expense research
and development costs as incurred. In addition, research and development costs include the costs of product supply received from suppliers when such receipt by us is prior to regulatory approval of the supplier.

(Loss) Gain on Change in Fair Value of Derivative Liabilities. (Loss) gain on change in fair value of derivative liabilities is
comprised of: (i) the change in fair value of the warrant derivative liability, (ii) the change in fair value of the derivative liability related to the change in control provision associated with the December 2012 BioPharma financing and
(iii) the change in fair value of the derivative liabilities related to the change in control provisions associated with the May 2014 and November 2015 exchangeable senior notes.

Our discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements and notes, which have been prepared in accordance with accounting
principles generally accepted in the United States. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenue and expenses. On an ongoing basis, we
evaluate our estimates and judgments, including those related to derivative financial liabilities. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances, the results
of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. A summary of
our significant accounting policies is contained in Note 2 to our consolidated financial statements included elsewhere in this Annual Report on Form 10-K. We believe the following critical accounting policies affect our more significant judgments
and estimates used in the preparation of our consolidated financial statements.

Revenue RecognitionWe sell
Vascepa principally to a limited number of Distributors, that in turn resell Vascepa to retail pharmacies that subsequently resell it to patients and healthcare providers. In accordance with GAAP, our revenue recognition policy requires that:
(i) there is persuasive evidence that an arrangement exists between us and the Distributor, (ii) delivery has occurred, (iii) collectability is reasonably assured and (iv) the price is fixed or determinable.

We began recognizing revenue from the sale of Vascepa following our commercial launch in the United States in January 2013. Prior to
2013, we recognized no revenue from Vascepa sales. We sell Vascepa to

Distributors. In accordance with GAAP, until we had the ability to reliably estimate returns of Vascepa from our Distributors, revenue was recognized based on the resale of Vascepa for the
purposes of filling patient prescriptions, and not based on our sales to such Distributors. During the three months ended March 31, 2014, we concluded that we had developed sufficient history such that we can reliably estimate returns and as a
result, began to recognize revenue based on sales to our Distributors. Consequently, we recognized revenues of $81.0 million and $54.2 million based on sales to Distributors during the years ended December 31, 2015 and 2014, respectively.
Through December 31, 2015, product returns were de minimis.

We have written contracts with our Distributors, and
delivery occurs when a Distributor receives Vascepa. We evaluate the creditworthiness of each of our Distributors to determine whether revenues can be recognized upon delivery, subject to satisfaction of the other requirements, or whether
recognition is required to be delayed until receipt of payment. In order to conclude that the price is fixed or determinable, we must be able to (i) calculate our gross product revenues from the sales to Distributors and (ii) reasonably
estimate our net product revenues. We calculate gross product revenues based on the wholesale acquisition cost that we charge our Distributors for Vascepa. We estimate our net product revenues by deducting from our gross product revenues
(a) trade allowances, such as invoice discounts for prompt payment and distributor fees, (b) estimated government and private payor rebates, chargebacks and discounts, such as Medicaid reimbursements, (c) reserves for expected product
returns and (d) estimated costs of incentives offered to certain indirect customers, including patients. The gross to net deductions are estimated based on available actual information, historical data, known trends, and levels of inventory in
the distribution channel. We rely on resale data provided by our Distributors as well as prescription data provided by Symphony Health Solutions and IMS Health in estimating the level of inventory held in the distribution channel. A hypothetical 5%
change in estimated channel inventory would result in a less than 0.5% change in product revenues reported during the three and twelve months ended December 31, 2015.

When evaluating multiple-element arrangements, we identify the deliverables included within the agreement and evaluate which deliverables represent separate units of accounting based on whether the
delivered element has stand-alone value to the collaborator or if the arrangement includes a general right of return for delivered items. We may receive up-front, non-refundable payments when licensing our intellectual property in conjunction with
research and development agreements. In determining the units of accounting, we evaluate whether the license has stand-alone value from the undelivered elements to the collaborative partner based on the consideration of the relevant facts and
circumstances for each arrangement. Factors considered in this determination include the stage of development of the license delivered, research and development capabilities of the partner and the ability of partners to develop and commercialize
Vascepa independently.

When we believe a license to our intellectual property does not have stand-alone value from the other
deliverables to be provided in the arrangement, we generally recognize revenue attributable to the license over the contractual or estimated performance period. Any unrecognized portion of license revenue is classified within deferred revenue in the
accompanying consolidated balance sheets. When we believe a license to our intellectual property has stand-alone value, we recognize revenue attributed to the license upon delivery. The periods over which revenue is recognized is subject to
estimates and may change over the course of the agreement. Such a change could have a material impact on the amount of revenue we record in future periods.

Derivative Financial LiabilitiesDerivative financial liabilities are initially recorded at fair value. They are subsequently held at fair value, with gains and losses arising for changes in
fair value recognized in the statement of operations. The fair value of derivative financial liabilities is determined using various valuation techniques. We use our judgment to select a variety of methods and make assumptions that are mainly based
on market conditions existing at each balance sheet date, which include our projections for future estimated revenues, management estimates of the probability of a change in control occurring, and the terms of debt issues of similar companies.
Fluctuations in the assumptions used in the valuation model would result in adjustments to the fair value of the derivative liabilities reflected on our balance sheet and, therefore, our statement of operations. If we issue shares to discharge the
liability, the derivative financial liability is derecognized and common stock and

additional paid-in capital are recognized on the issuance of those shares. For options and warrants treated as derivative financial liabilities, at settlement date the carrying value of the
options and warrants are transferred to equity. The cash proceeds received from shareholders for additional shares are recorded in common stock and additional paid-in capital. We have recorded financial derivatives related to certain outstanding
warrants (extinguished as of December 31, 2015), the change in control provision associated with our December 2012 debt financing and the change in control provision associated with our May 2014 and November 2015 exchangeable senior notes.

InventoryPrior to July 26, 2012, when we received approval from the FDA to market and sell Vascepa in the
United States for the MARINE indication, Vascepa was considered a product candidate under development. All supply of Vascepa purchased prior to July 26, 2012 was not capitalized and instead charged as a component of research and development
expense in the period received. After Vascepa was approved, we began to capitalize inventory purchased from Nisshin, the API supplier approved in the NDA. Prior to April 2013, Nisshin was the only FDA-approved supplier of API for Vascepa. In 2013,
the FDA qualified additional API suppliers to produce Vascepa with approval of our sNDAs covering Chemport, Slanmhor Pharmaceutical, Inc., or Slanmhor, in a consortium which included Novasep as the manufacturer for Slanmhor, and a fourth API
supplier which we subsequently reached mutual agreement to terminate due to production challenges. All supply purchases from API suppliers prior to FDA approval of these API suppliers in 2013 were not capitalized and instead charged as a component
of research and development expense in the period received. Subsequent to the approval of these suppliers, we capitalize API purchases from them. Until an API supplier is approved, all Vascepa API purchased from such supplier is included as a
component of research and development expense. Upon sNDA approval of each additional supplier, we capitalize subsequent Vascepa API purchases from such supplier as inventory. We state inventories at the lower of cost or market value. Cost is
determined based on actual cost using the average cost method. An allowance is established when management determines that certain inventories may not be saleable. If inventory cost exceeds expected market value due to obsolescence, damage or
quantities in excess of expected demand, we will reduce the carrying value of such inventory to market value. We expense inventory identified for use as marketing samples when they are packaged. The average cost reflects the actual purchase price of
Vascepa API. Additionally, the determination of the classification of our inventory requires the use of estimates in order to determine the portion of inventories anticipated to be utilized within twelve months of the balance sheet date.

Income TaxesDeferred tax assets and liabilities are recognized for the future tax consequences of differences between the
carrying amounts and tax bases of assets and liabilities and operating loss carryforwards and other attributes using enacted rates expected to be in effect when those differences reverse. Valuation allowances are provided against deferred tax assets
that are not more likely than not to be realized.

We provide reserves for potential payments of tax to various tax
authorities or do not recognize tax benefits related to uncertain tax positions and other issues. Tax benefits for uncertain tax positions are based on a determination of whether a tax benefit taken by us in our tax filings or positions is more
likely than not to be realized, assuming that the matter in question will be decided based on its technical merits. Our policy is to record interest and penalties in the provision for income taxes.

We assess our ability to realize deferred tax assets at each reporting period. The realization of deferred tax assets depends on
generating future taxable income during the periods in which the tax benefits are deductible or creditable. We have been historically profitable in the United States. When making our assessment about the realization of its U.S. deferred tax assets
as of December 31, 2015, we considered all available evidence, placing particular weight on evidence that could be objectively verified. The evidence considered included the (i) historical profitability of our U.S. operations,
(ii) sources of future taxable income, giving weight to sources according to the extent to which they can be objectively verified and (iii) the risks to our business related to the commercialization and development of Vascepa. Based on our
assessment, we concluded that the U.S. deferred tax assets are more likely than not to be realizable as of December 31, 2015. The majority of our deferred tax assets are held outside of the United States, for which we have established a full
valuation allowance. Changes in

historical earnings performance and future earnings projections, among other factors, may cause us to adjust our valuation allowance on deferred tax assets, which would impact our income tax
expense in the period in which we determine that these factors have changed. In the event sufficient taxable income is not generated in future periods, additional valuation allowances could be required relating to these U.S. deferred tax assets.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or FASB, and are adopted by us as of the specified effective date. We considered the following
recent accounting pronouncements which were not yet adopted as of December 31, 2015:

In May 2014, the FASB issued ASU
No. 2014-09, Revenue from Contracts with Customers (Topic 606). This amendment provides principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to
be entitled in exchange for those goods or services, and is effective for annual periods beginning after December 15, 2016 (the original effective date). In April 2015, the FASB issued a proposal, which was subsequently adopted in July 2015, to
defer the original effective date of this standard by one year, such that the amendment is effective for our fiscal year beginning January 1, 2018. Early adoption is permitted, but not before the original effective date. We are currently
evaluating the accounting, transition and disclosure requirements of the standard and cannot currently estimate the financial statement impact of adoption.

In June 2014, the FASB issued guidance for accounting for share-based payments when the terms of an award provide that a performance target could be achieved after the requisite service period. The
standard states that a performance target in a share-based payment that affects vesting and that could be achieved after the requisite service period should be accounted for as a performance condition. As such, the performance target should not be
reflected in estimating the grant-date fair value of the award. We are required to adopt this standard in the first quarter of fiscal 2016 and early adoption is permitted. This standard is not expected to have an impact on our consolidated financial
statements.

In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial StatementsGoing Concern
(Subtopic 205-40): Disclosure of Uncertainties about an Entitys Ability to Continue as a Going Concern. ASU 2014-15 requires management to assess an entitys ability to continue as a going concern by incorporating and expanding upon
certain principles that are currently in U.S. auditing standards. Specifically, the ASU (i) provides a definition of the term substantial doubt, (ii) requires an evaluation every reporting period including interim periods,
(iii) provides principles for considering the mitigating effect of managements plans, (iv)requires certain disclosures when substantial doubt is alleviated as a result of consideration of managements plans, (v) requires an
express statement and other disclosures when substantial doubt is not alleviated and (vi) requires an assessment for a period of one year after the date that the financial statements are issued (or available to be issued). This standard is
effective for the fiscal years ending after December 15, 2016, and for annual and interim periods thereafter. Early application is permitted. We have determined that this standard would not have a material impact on our consolidated financial
statements based on the assessment of our ability to continue as a going concern as of December 31, 2015.

In April 2015,
the FASB issued ASU No. 2015-03, InterestImputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The amendments in this ASU require that debt issuance costs related to a recognized debt
liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. We are required to adopt this standard in the first quarter of fiscal 2016 on a retrospective basis.
The implementation of this standard will result in the reclassification of certain debt issuance costs from other assets to a reduction in the carrying amount of the related debt liability within the consolidated balance sheets.

In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): Simplifying
the Measurement of Inventory. The amendments in this ASU require that in-scope inventory should be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business,
less reasonably predictable costs of completion, disposal, and transportation. The amendments do not apply to inventory that is measured using last-in, first-out (LIFO) or the retail inventory method but applies to all other inventory, which include
inventory that is measured using first-in, first-out (FIFO) or average cost. This standard is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early application is permitted. We
are currently evaluating the accounting, transition and disclosure requirements of the standard and cannot currently estimate the financial statement impact of adoption.

In January 2016, the FASB issued ASU No. 2016-01, Financial InstrumentsOverall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The new
guidance is intended to improve the recognition and measurement of financial instruments by requiring separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (i.e., securities or loans
and receivables) on the balance sheet or the accompanying notes to the financial statements, eliminating the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is
required to be disclosed for financial instruments measured at amortized cost on the balance sheet, requiring public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes,
requiring equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, and requiring a
reporting organization to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk (also referred to as own credit)
when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments, among others. The new guidance is effective for fiscal years beginning after December 15, 2017,
including interim periods within those fiscal years. The new guidance permits early adoption of the own credit provision. We are currently evaluating the accounting, transition and disclosure requirements of the standard and cannot currently
estimate the financial statement impact of adoption.

We believe that the impact of other recently issued but not yet adopted
accounting pronouncements will not have a material impact on consolidated financial position, results of operations, and cash flows, or do not apply to our operations.

Effects of Inflation

We believe the impact of inflation on operations has
been minimal during the past three years.

Results of Operations

Comparison of Fiscal Years Ended December 31, 2015 and December 31, 2014

Product Revenue, net. We recorded product revenue of $81.0 million and $54.2 million during the years ended December 31, 2015 and 2014, respectively, an increase of $26.8 million, or 49%. This
increase in revenue was driven by an increase in estimated normalized total Vascepa prescriptions of approximately 228,000 and 258,000 based on data provided by Symphony Health Solutions and IMS Health, respectively, representing growth of 55% and
62%, respectively, over the year ended December 31, 2014. The difference in the percentage of revenue growth as compared to the percentage of prescription growth is primarily due to a change in revenue recognition methodology in 2014 as
described below. The level of inventories held by our customers as of December 31, 2015 was slightly lower as compared to inventories held as of December 31, 2014 based on days on hand. All of our product revenue in the years ended
December 31, 2015 and 2014 was derived from product sales of Vascepa, net of allowances, discounts, incentives, rebates, chargebacks and returns. In accordance with GAAP, prior to 2014, product revenue was recognized based on the resale of
Vascepa for the purposes of filling patient prescriptions and not based on sales to our Distributors. During the three months ended March 31, 2014,

we concluded that we had developed sufficient history such that we can reliably estimate returns and, as a result, began to recognize product revenue based on sales to our Distributors. Through
December 31, 2015, product returns of Vascepa were de minimis. Timing of shipments to wholesalers, as used for revenue recognition, and timing of prescriptions as estimated by third-party sources such as Symphony Health Solutions and IMS Health
may differ from period to period.

During the years ended December 31, 2015 and 2014, our net product revenue included an
adjustment for co-pay mitigation rebates provided by us to commercially insured patients. Such rebates are intended to offset the differential for patients of Vascepa not covered by commercial insurers at the time of launch on Tier 2 for formulary
purposes, resulting in higher co-pay amounts for such patients. Our cost for these co-payment mitigation rebates was up to $75 per prescription filled prior to February 20, 2014 and up to $70 per prescription filled after February 20,
2014. Since launch, certain third-party payors have added Vascepa to their Tier 2 coverage, which results in lower co-payments for patients covered by these third-party payors. In connection with such Tier 2 coverage, we have agreed to pay customary
rebates to these third-party payors on the resale of Vascepa to patients covered by these third-party payors. As is typical for the pharmaceutical industry, the majority of Vascepa sales are to major commercial wholesalers which then resell Vascepa
to retail pharmacies.

Licensing Revenue. Licensing revenue during the year ended December 31, 2015 was $0.8
million. We did not record licensing revenue prior to 2015. The licensing revenue relates to the amortization of a $15.0 million up-front payment received in February 2015 associated with a Vascepa licensing agreement for the China Territory. The
up-front payment is being recognized over the estimated period in which we are required to provide regulatory and development support and clinical and commercial supply, which is currently anticipated to be a period of approximately 16 years. The
amount of licensing revenue recorded may be variable from period to period based on changes in estimates of the timing and level of support required.

Cost of Goods Sold. Cost of goods sold during the years ended December 31, 2015 and 2014 was $27.9 million and $20.5 million, respectively, an increase of $7.4 million, or 36%. Cost of goods
sold includes the cost of API for Vascepa on which revenue was recognized during the period, as well as the associated costs for encapsulation, packaging, shipment, supply management, insurance and quality assurance. The cost of the API included in
cost of goods sold reflects the average cost of API included in inventory. This average cost reflects the actual purchase price of Vascepa API.

The API included in the calculation of the average cost of goods sold was sourced from three API suppliers for the year ended December 31, 2015 and from two API suppliers for the year ended December
31, 2014. The contracted cost of supply from our initial API supplier was higher than the contracted cost from our other API suppliers. In the future, we anticipate making continued purchases from this initial supplier and to make additional lower
unit cost purchases of Vascepa API from other API suppliers, with the amount of such purchases dependent on the rate of our revenue growth.

Our gross margin on product sales for the years ended December 31, 2015 and 2014 was 66% and 62%, respectively. This improvement was primarily driven by lower unit cost API purchases. In addition,
over time we expect continued lower average unit cost purchases of API. We also expect that API costs will be lower in the future due to advantages derived from the mix of our suppliers. The average cost may be variable from period to period
depending upon the timing and quantity of API purchased from each supplier.

Selling, General and Administrative Expense. Selling, general and administrative
expense for the years ended December 31, 2015 and 2014 was $101.0 million and $79.3 million, respectively, an increase of $21.7 million, or 27%. Selling, general and administrative expenses for the years ended December 31, 2015 and 2014
are summarized in the table below (in thousands):

Year EndedDecember 31,

2015

2014

Selling, general and administrative expense (1)

$

82,474

$

71,864

Co-promotion fees (2)

7,967

1,664

Non-cash stock based compensation expense (3)

10,609

6,321

Non-cash warrant related compensation income

(9

)

(503

)

Total selling, general and administrative expense

$

101,041

$

79,346

(1)

Selling, general and administrative expense, excluding non-cash compensation charges for stock compensation and warrants and co-promotion fees, for the years ended
December 31, 2015 and 2014 was $82.5 million and $71.9 million, respectively, an increase of $10.6 million, or 15%. The increase is due primarily to increased sales and marketing spend in support of expanded Vascepa promotion following the
federal court declaration on August 7, 2015 allowing communication of truthful and non-misleading ANCHOR clinical trial data to be communicated to healthcare professionals, as well as higher legal costs associated with various legal matters,
which costs vary from period to period.

(2)

Co-promotion fees payable to Kowa Pharmaceuticals America, Inc. were $8.0 million and $1.7 million in the years ended December 31, 2015 and 2014, respectively, an
increase of $6.3 million, or 371%. Kowa Pharmaceuticals America, Inc. commenced its co-promotion efforts in May 2014.

(3)

Stock-based compensation expense for the years ended December 31, 2015 and 2014 was $10.6 million and $6.3 million, respectively, an increase of $4.3 million, or
68%, primarily due to an increase in new stock option and restricted stock awards granted to attract and retain qualified employees.

We currently anticipate that prior to REDUCE-IT data, our selling, general and administrative costs in 2016 will be substantially consistent with that in 2015, with the exception of non-cash costs and
anticipated increases in the co-promotion fees earned by Kowa Pharmaceuticals America, Inc. based on anticipated increases in net product revenues and the terms of our co-promotion agreement with Kowa Pharmaceuticals America, Inc.

Research and Development Expense. Research and development expense for the years ended December 31, 2015 and 2014 was $51.1
million and $50.3 million, respectively, an increase of $0.8 million, or 2%. Research and development expenses for the years ended December 31, 2015 and 2014 are summarized in the table below (in thousands):

Year EndedDecember 31,

2015

2014

REDUCE-IT study (1)

$

34,706

$

37,672

Regulatory filing fees and expenses (2)

2,162

1,847

Internal staffing, overhead and other (3)

10,914

8,106

Research and development expense, excluding non-cash expense

47,782

47,625

Non-cash stock-based compensation (4)

3,280

2,701

Total research and development expense

$

51,062

$

50,326

The increase in research and development expenses for the year ended December 31, 2015, as compared
to the prior year period, is primarily due to an increase in internal staffing and overhead costs and non-cash stock-based compensation partially offset by quarterly variability in costs related to the REDUCE-IT study.

In December 2011, we announced commencement of patient dosing in our cardiovascular outcomes study of Vascepa, titled REDUCE-IT, which is designed to evaluate the
efficacy of Vascepa in reducing major cardiovascular events in a high-risk patient population on statin therapy. The study duration is dependent on the rate of clinical events in the study, which rate may be affected by the number of patients
enrolled in the study, the epidemiology of the patients enrolled in the study, and the length of time that the enrolled patients are followed. We manage the study through a CRO through which all costs for this outcomes study are incurred with the
exception of costs for CTM and costs for internal management. Our internal personnel are responsible for managing multiple projects and their costs are not specifically allocated to REDUCE-IT or any other individual project. For the years ended
December 31, 2015 and 2014, we incurred expenses through our CRO in connection with this trial of approximately $28.5 million and $31.0 million, respectively. Inclusive of CTM costs, the combined CRO and CTM costs during the years ended
December 31, 2015 and 2014 for REDUCE-IT were approximately $34.7 million and $37.7 million, respectively. The decrease in expenses in 2015 as compared to 2014 is primarily the result of timing variability for REDUCE-IT costs. We expense costs
for CTM when allocated to clinical research. The aggregate cost of this outcomes study will depend on the rate of clinical events in the study. We currently estimate we will incur $30 million to $40 million in annual costs through study completion
and the rate at which we incur such costs will vary from quarter to quarter. The study is designed to be completed after reaching 1,612 aggregate cardiovascular events. Based on projected event rates, we estimate the onset of the target aggregate
number of cardiovascular events to be reached in or about 2017 with study results then expected to be available and published in 2018. We anticipate that our costs for this outcomes study will continue to represent the most significant component of
our research and development expenditures.

(2)

The regulatory filing fees in each of the years ended December 31, 2015 and 2014 included annual FDA fees for maintaining manufacturing sites.

(3)

Internal staffing, overhead and other research and development expenses primarily relate to the costs of our personnel employed to manage research, development and
regulatory affairs activities and related overhead costs including consulting and other professional fees that are not allocated to specific projects. Also included are costs related to qualifying suppliers and legal costs.

(4)

Non-cash stock-based compensation expense represents the costs associated with equity awards issued to internal staff supporting our research and development and
regulatory functions.

Research and development costs, excluding non-cash costs, are expected to vary from
quarter to quarter in 2016 due to the timing of REDUCE-IT costs.

(Loss) Gain on Change in Fair Value of Derivative
Liabilities. (Loss) gain on change in fair value of derivative liabilities for the year ended December 31, 2015 was a loss of $1.1 million versus a gain of $13.5 million in the prior year period. (Loss) gain on change in fair value of
derivative liabilities is comprised of (i) the change in fair value of the warrant derivative liability, (ii) the change in fair value of the derivative liability related to the change in control provision associated with the December 2012
BioPharma financing, (iii) the change in fair value of the derivative liabilities related to the change in control provisions associated with the May 2014 and November 2015 exchangeable senior notes; and (iv) the change in fair value of
the derivative liability related to the preferred stock purchase option.

The warrant derivative liability is related to the
change in fair value of warrants issued in conjunction with the October 2009 private placement. In October 2009, we issued 36.1 million warrants at an exercise price of $1.50 per warrant and recorded a $48.3 million warrant derivative
liability, representing the fair value of the warrants issued. As these warrants have been classified as a derivative liability, they are revalued at each reporting period, with changes in fair value recognized in the statement of operations. The
fair value of the warrant derivative liability as of December 31, 2014 was $0.1 million and we recognized a $0.1 million gain on change in fair value of derivative liability for the year ended December 31, 2015 for these warrants. The fair
value of the warrant derivative liability as of December 31, 2013 was $6.9 million and we recognized a $6.3 million gain on change in fair value of derivative liability for the year ended December 31, 2014. The change in

fair value of the warrant derivative liability for the year ended December 31, 2015 is due to the expiration of the warrants and the resulting extinguishment of the liability, while the
change in fair value for the year ended December 31, 2014 is due primarily to the change in the price of our common stock on the date of valuation. In October 2014, we and the holders of the remaining October 2009 warrants mutually agreed to
extend the expiration date of such warrants from October 16, 2014 to February 27, 2015. Of the 8,087,388 warrants outstanding as of December 31, 2014, 1,844,585 warrants were exercised and the remaining 6,242,803 warrants expired on
February 27, 2015. As such, no warrants were outstanding as of December 31, 2015.

Our December 2012 financing
agreement with BioPharma contains a redemption feature whereby, upon a change of control, we would be required to repay $150 million, less any previously repaid amount. The fair value of the derivative liability is recalculated at each reporting
period using a probability-weighted model incorporating management estimates for potential change in control, and by determining the fair value of the debt with and without the change in control provision included. The difference between the two
fair values of the debt was determined to be the fair value of the embedded derivative. As of December 31, 2014, the fair value of the derivative was determined to be $4.8 million, and as of December 31, 2015, the fair value of the
derivative was determined to be $5.5 million. As such, we recognized a $0.7 million loss on change in fair value of derivative liability for the year ended December 31, 2015. As of December 31, 2013, the fair value of the derivative was
determined to be $11.1 million, and as of December 31, 2014, the fair value of the derivative was determined to be $4.8 million. As such, we recognized a $6.3 million gain on change in fair value of derivative liability for the year ended
December 31, 2014.

Our 2014 Notes, issued in May 2014, contain a redemption feature whereby, upon occurrence of a change
in control, we would be required to repurchase the notes. The fair value of the embedded derivative was calculated using a probability-weighted model incorporating management estimates of the probability of a change in control occurring, and by
determining the fair value of the debt with and without the change in control provision included. The difference between the two was determined to be the fair value of the embedded derivative. As of December 31, 2014, the fair value of the
derivative was determined to be $2.6 million, and as of December 31, 2015, the fair value of the derivative was determined to be $2.1 million. As such, we recognized a $0.5 million gain on change in fair value of derivative liability for the
year ended December 31, 2015. Upon initial recording, the fair value of the derivative was determined to be $3.5 million, and as of December 31, 2014, the fair value of the derivative was determined to be $2.6 million. As such, we
recognized a $0.9 million gain on change in fair value of derivative liability for the year ended December 31, 2014.

Our
2015 Notes, issued in November 2015, contain the same redemption feature as the 2014 Notes and the related derivative liability was calculated utilizing the same methodology. Upon issuance in November 2015, the fair value of the derivative was
determined to be $0.5 million, and as of December 31, 2015, the fair value of the derivative was determined to be $0.6 million. As such, we recognized a $0.1 million loss on change in fair value of derivative liability for the year ended
December 31, 2015.

In connection with the closing of a private placement transaction in early March 2015, we recorded a
derivative liability pursuant to a pre-existing contractual right. This preferred stock purchase option was determined to be a derivative liability effective March 5, 2015, the date in which the private placement was initially subscribed. The
fair value of this liability was calculated using a Black-Scholes model and was determined to be $0.9 million at inception. The liability was charged to accumulated deficit as a deemed non-cash dividend and is therefore reflected as an adjustment to
net loss applicable to common shareholders for earnings per common share purposes in accordance with GAAP. The liability was then marked to fair value through March 30, 2015, the date on which we executed a separate subscription agreement with
the investor, resulting in a charge of $0.9 million through (loss) gain on change in fair value of derivatives in the year ended December 31, 2015. The liability was reclassified to permanent equity on such date.

The change in fair value of the derivative liability related to the BioPharma financing agreement is largely related to our projections
for future estimated revenues, management estimates of the probability of a change in

control occurring, and the terms of debt issues of similar companies. The change in fair value of the derivative liabilities related to the 2014 Notes and 2015 Notes is largely related to changes
in quoted bond prices. Any changes in the assumptions used to value the derivative liabilities could result in a material change to the carrying value of such liabilities.

Gain on Extinguishment of Debt. On May 15, 2014, we entered into separate, privately negotiated exchange agreements with certain holders of our exchangeable senior notes pursuant to which we
exchanged $118.7 million in aggregate principal amount of existing exchangeable senior notes for $118.7 million in aggregate principal amount of new 3.5% exchangeable senior notes due 2032. The key changes in the terms of the new notes included
moving the first put date from January 2017 to January 2019, adding an issuer conversion option whereby we can opt to convert the notes into equity should the Daily VWAP (as defined in the Indenture) exceed $2.86 for a certain number of days and
reducing the conversion price (see Note 8). As a result of the exchange, we assessed the value of the notes immediately prior to the exchange and immediately after the exchange and determined that the exchange resulted in a substantial modification
of the terms of the notes resulting in an extinguishment of the original notes. We recorded a gain on extinguishment of the original notes of $38.0 million in the year ended December 31, 2014.

In November 2015, we entered into a privately negotiated subscription agreement with one of our existing investors (the
Investor), pursuant to which the Investor agreed to purchase approximately $31.3 million in aggregate principal amount of new 3.5% November 2015 Exchangeable Senior Notes due 2032 (the 2015 Notes) for approximately $27.5
million. Concurrent with the issuance of the 2015 Notes, we entered into separate, privately negotiated purchase agreements with certain holders of the 3.5% January 2012 Exchangeable Senior Notes due 2032 (the 2012 Notes) pursuant
to which we purchased approximately $16.2 million in aggregate principal amount of the 2012 Notes for $15.9 million (the 2012 Notes Purchase), which includes accrued but unpaid interest on such 2012 Notes. The 2012 Notes Purchase was
funded by the issuance of the 2015 Notes. Following the closing of the 2012 Notes Purchase, we had approximately $15.1 million in aggregate principal amount of 2012 Notes outstanding. The 2012 Notes Purchase was accounted for as an extinguishment of
debt and we recorded a gain of $1.3 million upon extinguishment, which represents the reacquisition of the conversion option at fair value and a negotiated discount on the purchase of the notes partially offset by legal and transaction advisory
costs incurred.

Interest Expense, net. Net interest expense for the years ended December 31, 2015 and 2014 was
$20.0 million and $18.5 million, respectively, an increase of $1.5 million, or 8%. Net interest expense for the years ended December 31, 2015 and 2014 is summarized in the table below (in thousands):

Cash and non-cash interest expense related to the exchangeable senior notes for the years ended December 31, 2015 and 2014 was $11.7 million and $9.5 million,
respectively.

(2)

Cash and non-cash interest expense related to the BioPharma financing for the years ended December 31, 2015 and 2014 was $8.5 million and $9.1 million,
respectively. These amounts reflect the assumption that our Vascepa revenue levels will not be high enough to support repayment to BioPharma in accordance with the repayment schedule without the optional reduction which is allowed to be elected by
us if the threshold revenue levels are not achieved. To date, our revenues have been below the contractual threshold amount each quarter such that each payment reflects the calculated optional reduction amount as opposed to the contractual threshold
payments for each quarterly period.

(3)

Interest income for the years ended December 31, 2015 and 2014 was $0.1 million in each year. Interest income represents income earned on cash balances.

Other (Expense) Income, net. Other (expense) income, net, for the years ended December 31, 2015 was
expense of $0.2 million versus income of $3.7 million in the prior year period. Other (expense) income, net, in the year ended December 31, 2015 primarily consists of losses and gains on foreign exchange transactions. Other (expense) income,
net in the year ended December 31, 2014 primarily consists of $4.1 million received in the second quarter of 2014 with respect to settlement agreements with one of our suppliers and one of our encapsulators that provided for the reimbursement
of certain amounts previously paid by us.

Benefit from Income Taxes. Benefit from income taxes for the years ended
December 31, 2015 and 2014 was $3.1 million and $2.8 million, respectively. The current benefit relates entirely to the U.S. subsidiary operations. We are profitable in the United States as a result of intercompany transactions between our U.S.
subsidiary and our other companies.

Preferred Stock Beneficial Conversion Features. We issued Series A preference
shares in a private placement transaction executed in two tranches that each contain a conversion feature whereby such shares are convertible into ordinary shares at a fixed rate (see Note 10). The conversion price on the date of issuance was less
than the market price of our ordinary shares. We determined that these discounts represent contingent beneficial conversion features, which were valued based on the difference between the conversion price and the market price of the ordinary shares
on the date of issuance. These features, totaling $33.0 million, are analogous to preference dividends and were each recorded as a non-cash return to preferred shareholders through accumulated deficit, and are therefore reflected as an adjustment to
net loss applicable to common shareholders for earnings per common share purposes in accordance with GAAP. There was no such adjustment in the year ended December 31, 2014.

Comparison of Fiscal Years Ended December 31, 2014 versus December 31, 2013

Product Revenue, net. We recorded revenue of $54.2 million during the year ended December 31, 2014, versus $26.4 million during the prior year period, an increase of $27.8 million, or 105%. We
commenced our full commercial launch of Vascepa in the United States for use in the MARINE indication in January 2013. All of our revenue in the years ended December 31, 2014 and 2013 was derived from product sales of Vascepa, net of
allowances, discounts, incentives, rebates, chargebacks and returns.

We sell Vascepa to Distributors. In accordance with
GAAP, until we had the ability to reliably estimate returns of Vascepa from our Distributors, revenue was recognized based on the resale of Vascepa for the purposes of filling patient prescriptions, and not based on our sales to such Distributors.
Beginning in January 2014, we concluded that we had developed sufficient history such that we can reliably estimate returns and as a result, began to recognize revenue based on sales to our Distributors. Through December 31, 2014, product
returns were de minimis. Timing of shipments to wholesalers, as used for revenue recognition, and timing of prescriptions as estimated by third-party sources such as Symphony Health Solutions and IMS Health may differ from period to period.

During the years ended December 31, 2014 and 2013, our net product revenues included an
adjustment for co-pay mitigation rebates provided by us to commercially insured patients. Such rebates are intended to offset the differential for patients of Vascepa not covered by commercial insurers at the time of launch on Tier 2 for formulary
purposes, resulting in higher co-pay amounts for such patients. Our cost for these co-payment mitigation rebates was up to $75 per prescription filled prior to February 20, 2014 and up to $70 per prescription filled after February 20, 2014
to December 31, 2014. Commencing in March and April 2013, certain third-party payors added Vascepa to their Tier 2 coverage, which results in lower co-payments for patients covered by these third-party payors. As of February 1, 2015,
approximately 125 million lives covered by medical insurance were under insurance plans that have added Vascepa to their Tier 2 coverage. In connection with the start of such Tier 2 coverage, we have agreed to pay customary rebates to these
third-party payors on the resale of Vascepa to patients covered by these third-party payors.

As is typical for the
pharmaceutical industry, the majority of Vascepa sales are to major commercial wholesalers which then resell Vascepa to retail pharmacies. As of February 1, 2015, over 26,000 clinicians had written prescriptions for Vascepa. As of
February 1, 2015, we are not aware of any clinician who is responsible for 10% or more of the aggregate prescriptions written for Vascepa.

On October 22, 2013, in an effort to lower operating expenses following the recommendation of the advisory committee to the FDA, we implemented a worldwide reduction in force including a reduction of
approximately fifty percent of our sales representatives. Following the reduction in force, we retained approximately 130 sales representatives in the United States in sales territories which have demonstrated what we believe is the greatest
potential for Vascepa sales growth. This team will cover the target base of physicians responsible for the majority of Vascepa prescription volume and growth since its launch in early 2013. With these changes and resulting target base coverage, as
well as the addition of the promotional efforts of 250 sales representatives from Kowa Pharmaceuticals America, Inc. that began in May 2014, we anticipate continued Vascepa revenue growth over time. We further anticipate that such revenue growth may
be inconsistent from period to period.

Cost of Goods Sold. Cost of goods sold during the year ended December 31,
2014 was $20.5 million, versus $11.9 million during the prior year period, an increase of $8.6 million, or 72%. Cost of goods sold includes the cost of API for Vascepa on which revenue was recognized during the period, as well as the associated
costs for encapsulation, packaging, shipment, supply management, insurance and quality assurance. The cost of the API included in cost of goods sold reflects the average cost of API included in inventory. This average cost reflects the actual
purchase price of Vascepa API, as well as a portion of API carried at zero cost for material which was purchased prior to FDA approval of Vascepa on July 26, 2012 or was purchased prior to the sNDA approval of our suppliers.

The API included in the calculation of the average cost of goods sold during the years ended December 31, 2014 and 2013 was sourced
from two API suppliers. The contracted cost of supply from our initial API supplier was higher than the contracted cost from our other API supplier. In the future, we anticipate making continued purchases from this initial supplier and to make
additional lower unit cost purchases of Vascepa API from other API suppliers. We began purchasing lower unit cost API from Chemport, which was approved by the FDA in April 2013 to produce Vascepa, in the second quarter of 2013. During the years
ended December 31, 2014 and 2013, the cost basis of product sold that had a carrying value of zero was $0.6 million and $4.0 million, respectively. Had such inventories been valued at acquisition cost, it would have resulted in a corresponding
increase in cost of goods sold and a decrease in gross margin during such periods. As of December 31, 2014, we maintained no inventory with a carrying value of zero and we classified all of our inventory as current. As a result of lower
inventory balances on hand at the end of 2014 compared to the end of 2013 as well as increases in revenue during 2015 compared to 2014, we purchased more API during 2015 than in 2014 with the amount of future purchases dependent on the rate of our
revenue growth.

Our gross margin for the years ended December 31, 2014 and 2013 was 62% and 55%, respectively. This
improvement was primarily driven by lower unit cost API purchases. In addition, over time we expect continued

lower average unit cost purchases of API. We also expect that API costs will be lower in the future due to advantages derived from the mix of our suppliers. The average cost may be variable from
period to period depending upon the timing and quantity of API purchased from each supplier.

Selling, General and
Administrative Expense. Selling, general and administrative expense for the year ended December 31, 2014 was $79.3 million, versus $123.8 million in the prior year, a decrease of $44.5 million, or 36%. Selling, general and administrative
expenses for the years ended December 31, 2014 and 2013 are summarized in the table below (in thousands):

Year EndedDecember 31,

2014

2013

Selling, general and administrative expense (1)

$

73,528

$

113,100

Non-cash stock based compensation expense (2)

6,321

11,848

Non-cash warrant related compensation income (3)

(503

)

(3,703

)

Severance (4)



2,550

Total selling, general and administrative expense

$

79,346

$

123,795

(1)

Selling, general and administrative expense, excluding non-cash compensation charges for stock compensation and warrants, for the year ended December 31, 2014 was
$73.5 million, versus $113.1 million in the prior year, a decrease of $39.6 million, or 35%. The decrease is due primarily to cost decreases in 2014 for sales force staffing, marketing program spending and costs for other general and administrative
support incurred in connection with the commercialization of Vascepa. Included in this amount for the year ended 2014 is $1.7 million of expense for co-promotion fees payable to Kowa Pharmaceuticals America, Inc. The year ended December 31,
2013 was the period in which we commenced selling Vascepa and as such included certain launch-related costs.

(2)

Stock-based compensation expense for the year ended December 31, 2014 was $6.3 million, versus $11.8 million in the prior year period, a decrease of $5.5 million,
or 47%, primarily due to a decrease in the fair value of new stock option and restricted stock awards granted to attract and retain qualified employees as a result of a decrease in our stock price.

(3)

Warrant-related compensation income for the years ended December 31, 2014 and 2013 was $0.5 million and $3.7 million, respectively. Warrant-related compensation
income reflects the non-cash change in fair value of the warrant derivative liability associated with warrants issued in October 2009 to three of our former employees, net of warrants exercised. The decrease in fair value in 2014 and 2013 was due
primarily to a decrease in our stock price during each period.

(4)

Severance costs in 2013 relate to cash expenditures for one-time termination benefits and associated costs incurred in conjunction with a company-wide reduction in
force announced in October 2013.

The reduction in the level of selling, general and administrative costs in
2014 as compared to 2013 was primarily the result of the reduction in force announced in October 2013 and reductions in certain marketing program spend and other overhead costs. Such cost reductions were partially offset by the incremental selling
costs associated with the Kowa Pharmaceuticals America, Inc. co-promotion agreement.

Research and Development Expense. Research and development expense for the year ended
December 31, 2014 was $50.3 million, versus $72.8 million in the prior year period, a decrease of $22.5 million, or 31%. Research and development expenses for the years ended December 31, 2014 and 2013 are summarized in the table below (in
thousands):

Year EndedDecember 31,

2014

2013

REDUCE-IT study (1)

$

37,672

$

46,994

Pre-approval commercial supply (2)

373

5,819

Regulatory filing fees and expenses (3)

1,847

3,819

Internal staffing, overhead and other (4)

7,733

13,281

Research and development expense, excluding non-cash expense

47,625

69,913

Non-cash stock-based compensation (5)

2,701

2,837

Total research and development expense

$

50,326

$

72,750

The decrease in research and development expenses for the year ended December 31, 2014, as compared
to the prior year period, is primarily due to a decrease in costs associated with the REDUCE-IT study, a decrease in expenses associated with pre-commercial inventory supply, and a decrease in staffing and overhead costs, as further described below.

(1)

In December 2011, we announced commencement of patient dosing in our cardiovascular outcomes study of Vascepa, titled REDUCE-IT, which is designed to evaluate the
efficacy of Vascepa in reducing major cardiovascular events in a high risk patient population on statin therapy. The study duration is dependent on the rate of clinical events in the study, which rate may be affected by the number of patients
enrolled in the study, the epidemiology of the patients enrolled in the study, and the length of time that the enrolled patients are followed. We manage the study through a contract research organization (CRO) through which all costs for this
outcomes study are incurred with the exception of costs for clinical trial material (CTM) and costs for internal management. Our internal personnel are responsible for managing multiple projects and their costs are not specifically allocated to
REDUCE-IT or any other individual project. We estimate that we will complete patient enrollment in this study in March 2016. For 2014 and 2013, we incurred expenses through our CRO in connection with this trial of approximately $31.0 million and
$38.4 million, respectively. Inclusive of CTM costs, the combined CRO and CTM costs in 2014 and 2013 for REDUCE-IT were approximately $37.7 million and $47.0 million, respectively. The reduction in expenses in 2014 as compared to 2013 is primarily
the result of timing variability for REDUCE-IT costs as well as some efficiency savings as the trial is fully operational in 2014 across all countries and clinical sites. We expense costs for CTM upon receipt. The aggregate cost of this outcomes
study will depend on the rate of clinical events in the study. We currently estimate we will incur $30 million to $40 million in annual costs through study completion. Amarin remains blinded to all data from the study and currently expects the study
to be completed in 2017. There is a scheduled interim review of the efficacy and safety results of the study which review we estimate will occur in 2016 upon reaching 60% of the target aggregate number of cardiovascular events for the study. It is
our expectation that this trial will run to completion as is typical for cardiovascular outcome studies. We anticipate that our costs for this outcomes study will continue to represent the most significant component of our research and development
expenditures.

(2)

Until an API supplier is approved by the FDA to manufacture commercial supply of Vascepa, all Vascepa purchased from such supplier is included as a
component of research and development expense. Upon approval of the supplier, we capitalize subsequent Vascepa API purchases from such supplier as inventory. Purchases of Vascepa API received and expensed before such regulatory approvals are not
subsequently capitalized, and all such purchases are quarantined and not used for commercial supply until such time as the supplier that produced the API is approved. The commercial supply expense for the periods shown above represents inventory
received from Nisshin prior to NDA approval of Vascepa on July 26, 2012 or received from our other suppliers prior to their sNDA approvals. The amount of commercial supply that we

receive from potential additional API suppliers prior to sNDA approval depends upon production schedules at such suppliers and the timing of regulatory approval, and we are unable to estimate
these amounts at this time. We will continue to expense inventory received from the unapproved supplier until such time as FDA approval is obtained.

(3)

The regulatory filing fees in each of the years ended December 31, 2014 and 2013 included annual FDA fees for maintaining manufacturing sites. In addition, during
the year ended December 31, 2013, these fees included regulatory filings associated with the sNDA for the ANCHOR indication as well as costs associated with preparing for the October 16, 2013 FDA advisory committee meeting.

(4)

Internal staffing, overhead and other research and development expenses primarily relate to the costs of our personnel employed to manage research, development and
regulatory affairs activities and related overhead costs including consulting and other professional fees that are not allocated to specific projects. Also included are costs related to qualifying suppliers and legal costs. The reduction in the
level of such costs in 2014 as compared to 2013 is largely the result of decisions announced in October 2013 to reduce headcount and suspend AMR102 development. Other research and development costs in 2013 included costs related to testing of the
relative bioavailability of AMR102 capsules, Vascepa capsules with a selected statin taken concomitantly. We have suspended further development of AMR102 pending resolution of the ANCHOR sNDA with the FDA.

(5)

Non-cash stock-based compensation expense represents the costs associated with equity awards issued to internal staff supporting our research and development and
regulatory functions.

Gain (Loss) on Change in Fair Value of Derivative Liabilities. Gain (loss) on
change in fair value of derivative liabilities for the year ended December 31, 2014 was a gain of $13.5 million versus a gain of $47.7 million in the prior year period. Gain (loss) on change in fair value of derivative liabilities is comprised
of (i) the change in fair value of the warrant derivative liability, (ii) the change in fair value of the derivative liability related to the change in control provision associated with the December 2012 BioPharma financing, and
(iii) the change in fair value of the derivative liability related to the change in control provision associated with the May 2014 exchangeable senior notes.

The warrant derivative liability is related to the change in fair value of warrants issued in conjunction with the October 2009 private placement. In October 2009 we issued 36.1 million warrants at
an exercise price of $1.50 and recorded a $48.3 million warrant derivative liability, representing the fair value of the warrants issued. As these warrants have been classified as a derivative liability, they are revalued at each reporting period,
with changes in fair value recognized in the statement of operations. The fair value of the warrant derivative liability at December 31, 2014 was $0.1 million and we recognized a $6.3 million gain on change in fair value of derivative liability
for the year ended December 31, 2014 for these warrants. The fair value of the warrant derivative liability at December 31, 2013 was $6.9 million and we recognized a $44.2 million gain on change in fair value of derivative liability for
the year ended December 31, 2013. The change in fair value of the warrant derivative liability is due primarily to the change in the price of our common stock on the date of valuation. In October 2014, we and the holders of the remaining
October 2009 warrants mutually agreed to extend the expiration date of such warrants from October 16, 2014 to February 27, 2015.

Our December 2012 financing agreement with BioPharma contains a redemption feature whereby,
upon a change of control, we would be required to pay $140 million, less any previously repaid amount, if the change of control occurs on or before December 31, 2013, or required to repay $150 million, less any previously repaid amount, if the
change of control event occurs after December 31, 2013. The fair value of the derivative liability is recalculated at each reporting period using a probability-weighted model incorporating management estimates for potential change in control,
and by determining the fair value of the debt with and without the change in control provision included. The difference between the two fair values of the debt was determined to be the fair value of the embedded derivative. At December 31,
2014, the fair value of the derivative was determined to be $4.8 million, and at December 31, 2013, the fair value of the derivative was determined to be $11.1 million. We recognized a gain on change in fair value of derivative liability of
$6.3 million and $3.5 million for the years ended December 31, 2014 and 2013, respectively.

Our 2014 Notes contain a
redemption feature whereby, upon occurrence of a change in control, we would be required to repurchase the notes. The fair value of the embedded derivative was calculated using a probability-weighted model incorporating management estimates of the
probability of a change in control occurring, and by determining the fair value of the debt with and without the change in control provision included. The difference between the two was determined to be the fair value of the embedded derivative. At
December 31, 2014, the fair value of the derivative was determined to be $2.6 million and we recognized a $0.9 million gain on change in fair value of derivative liability for the year ended December 31, 2014.

Any changes in the assumptions used to value the derivative liabilities could result in a material change to the carrying value of such
liabilities.

Gain on Extinguishment of Debt. On May 15, 2014, we entered into separate, privately negotiated
exchange agreements with certain holders of our exchangeable senior notes pursuant to which we exchanged $118.7 million in aggregate principal amount of existing exchangeable senior notes for $118.7 million in aggregate principal amount of new 3.5%
exchangeable senior notes due 2032. The key changes in the terms of the new notes included moving the first put date from January 2017 to January 2019, adding an issuer conversion option whereby we can opt to convert the notes into equity should the
Daily VWAP (as defined in the Indenture) exceed $2.86 for a certain number of days and reducing the conversion price (see Note 8 to our consolidated financial statements included in this Annual Report on Form 10-K). As a result of the exchange, we
assessed the value of the notes immediately prior to the exchange and immediately after the exchange and determined that the exchange resulted in a substantial modification of the terms of the notes resulting in an extinguishment of the original
notes. We subsequently recorded a gain on extinguishment of the original notes of $38.0 million in the year ended December 31, 2014.

Interest Expense, net. Net interest expense for the year ended December 31, 2014
was $18.5 million, versus $33.8 million in the prior year period, a decrease of $15.3 million, or 45%. Net interest expense for the years ended December 31, 2014 and 2013 is summarized in the table below (in thousands):

Year EndedDecember 31,

2014

2013

Exchangeable senior notes (1):

Amortization of debt discounts

$

4,221

$

15,067

Contractual coupon interest

5,250

5,250

Total exchangeable senior notes interest expense

9,471

20,317

Long-term debtBioPharma financing (2):

Cash interestcurrent

5,420

1,843

Cash interestdeferred

1,783

9,451

Non-cash interest

1,900

2,565

Total long-term debt interest expense

9,103

13,859

Other interest expense

1

3

Total interest expense

18,575

34,179

Interest income (3)

(96

)

(343

)

Total interest expense, net

$

18,479

$

33,836

(1)

Cash and non-cash interest expense related to the exchangeable senior notes for the years ended December 31, 2014 and 2013 was $9.5 million and $20.3 million,
respectively.

(2)

Cash and non-cash interest expenses related to the BioPharma financing for the year ended December 31, 2014 were $9.1 million and $13.9 million, respectively.
These amounts reflect the assumption that our Vascepa revenue levels will not be high enough to support repayment to BioPharma in accordance with the repayment schedule without the optional reduction which is allowed to be elected by us if the
threshold revenue levels are not achieved. To date, our revenues have been below the contractual threshold amount each quarter such that each payment reflects the calculated optional reduction amount as opposed to the contractual threshold payments
for each quarterly period.

(3)

Interest income for the year ended December 31, 2014 was $0.1 million, versus $0.3 million in the prior year period. Interest income represents income earned on
cash balances.

Other Income (Expense), net. Other income (expense), net, for the year ended
December 31, 2014 was income of $3.7 million versus an expense of $1.2 million in the prior year. Other income (expense), net, in the year ended December 31, 2014 primarily consists of $4.1 million received in the second quarter of 2014
with respect to settlement agreements with one of our suppliers and one of our encapsulators that provided for the reimbursement of certain amounts previously paid by us. Other income (expense), net, for the year ended December 31, 2013
primarily consisted of losses and gains on foreign exchange transactions, including realized gains and losses on foreign exchange forward contracts. We periodically use foreign exchange forward contracts to hedge against changes in exchange rates
for inventory purchases denominated in foreign currency.

Benefit From (Provision for) Income Taxes. Benefit from
(provision for) income taxes for the year ended December 31, 2014 was a $2.8 million benefit versus a $3.2 million benefit in the prior year. The current benefit relates entirely to the United States subsidiary operations. We are profitable in
the United States as a result of intercompany transactions between our United States subsidiary and our other companies. The 2013 benefit primarily relates to tax credits for research and development activities.

Our sources of liquidity as of December 31, 2015 include cash and cash equivalents of $107.0 million. Our projected uses of cash
include commercialization of Vascepa, the continued funding of the REDUCE-IT cardiovascular outcomes study, working capital and other general corporate activities. Our cash flows from operating, investing and financing activities, as reflected in
the consolidated statements of cash flows, are summarized in the following table (in millions):

Years Ended December 31,

2015

2014

2013

Cash (used in) provided by:

Operating activities

$

(84.8

)

$

(72.3

)

$

(190.3

)

Investing activities







Financing activities

72.2

0.3

121.6

Decrease in cash and cash equivalents

$

(12.6

)

$

(72.0

)

$

(68.7

)

Cash used by operating activities in 2015 compared to 2014 increased as a result of increased purchases
of supply during 2015 compared to 2014, partially offset by higher collections from product revenues, $15.0 million in up-front proceeds from the China licensing agreement, and other operating differences in 2015. We began 2014 with more than a year
of Vascepa in inventory and as a result purchased little Vascepa supply in 2014, with purchases of supply resuming on an as-needed basis at the start of 2015.

On December 6, 2012 we entered into a financing agreement with BioPharma. Under this agreement, we granted to BioPharma a security interest in future receivables and all related rights to Vascepa, in
exchange for $100 million received at the closing of the agreement which closing occurred in December 2012. We have agreed to repay BioPharma up to $150 million of future revenue and receivables. As of December 31, 2015, the net remaining
amount to be repaid to BioPharma is $137.3 million. To date, our revenues have been below the contractual threshold amount such that each payment made has reflected the calculated optional reduction amount as opposed to the contractual threshold
payments for each quarterly period. The maximum amount payable under the contractual threshold for 2016 is $47.6 million. The quarterly repayments through December 31, 2015 represented interest only. In accordance with the agreement with
BioPharma, quarterly differences between the calculated optional reduction amounts and the repayment schedule amounts are rescheduled for payment beginning in the second quarter of 2017. Any such deferred payments will remain subject to continued
application of the quarterly ceiling in amounts due established by the calculated threshold based on quarterly Vascepa revenues. No additional interest expense or liability is incurred as a result of such deferred repayments. The agreement does not
expire until $150 million in aggregate has been repaid. We can prepay an amount equal to $150 million less any previously repaid amount. We currently estimate that Vascepa revenue levels will not be high enough in each quarter to support repayment
to BioPharma in accordance with threshold amounts in the repayment schedule.

On January 9, 2012, Amarin, through our
wholly-owned subsidiary Corsicanto Limited, or Corsicanto, a private limited company incorporated under the laws of Ireland, completed a private placement of $150.0 million in aggregate principal amount of its 3.5% exchangeable senior notes due
2032, or the 2012 Notes. The proceeds we received from the January 2012 debt offering were approximately $144.3 million, net of fees and transaction costs. On May 20, 2014, we entered into separate, privately negotiated exchange agreements with
certain holders of the 2012 Notes pursuant to which Corsicanto exchanged $118.7 million in aggregate principal amount of the 2012 Notes for $118.7 million in aggregate principal amount of new 3.5% May 2014 Exchangeable Senior Notes due 2032, or
the 2014 Notes. In November 2015, $16.2 million of the 2012 Notes was extinguished, following which $15.1 million in aggregate principal amount of the 2012 Notes remain outstanding with terms unchanged.

On November 24, 2015, we entered into a privately negotiated subscription agreement with one of our existing investors (the
Investor), pursuant to which the Investor agreed to purchase approximately $31.3

million in aggregate principal amount of new 3.5% November 2015 Exchangeable Senior Notes due 2032 (the 2015 Notes) for approximately $27.5 million. The 2015 Notes have
substantially identical terms to the 2014 Notes, except that the 2015 Notes were issued by Amarin Corporation plc and are not guaranteed by any entity.

The 2012 Notes were issued pursuant to an indenture dated as of January 9, 2012, by and among Corsicanto, us as guarantor, and Wells Fargo Bank, National Association, as trustee. The notes are the
senior unsecured obligations of Corsicanto and are guaranteed by us. The 2012 Notes bear interest at a rate of 3.5% per annum, payable semi-annually in arrears on January 15 and July 15 of each year, beginning on July 15, 2012.
The notes mature on January 15, 2032, unless earlier repurchased, redeemed or exchanged. On or after January 19, 2017, we may elect to redeem for cash all or a portion of the notes for the principal amount of the notes plus accrued and
unpaid interest. On each of January 19, 2017, January 19, 2022 and January 19, 2027, the holders of the notes may require that we repurchase in cash the principal amount of the notes plus accrued and unpaid interest. At any time
prior to January 15, 2032, upon certain circumstances, which circumstances include our issuing a notice of redemption to the note holders, the price of our shares trading above 130% of the exchange price, or certain other events defined in the
note agreement, the holders of the notes may elect to convert the notes. The exchange rate for conversion is 113.4752 ADSs per $1,000 principal amount of the notes (equivalent to an initial exchange price of approximately $8.8125 per ADS), subject
to adjustment in certain circumstances, including adjustment if we pay cash dividends. Upon exchange, the notes may be settled, at our election, subject to certain conditions, in cash, ADSs or a combination of cash and ADSs.

The 2014 Notes were issued pursuant to an indenture dated May 20, 2014 by and among Corsicanto, us as grantor, and Wells Fargo Bank,
National Association, as trustee. The notes are senior unsecured obligations of Corsicanto and are guaranteed by us. The 2014 Notes have a stated interest rate of 3.5% per year, payable semiannually in arrears on January 15 and
July 15 of each year beginning on July 15, 2014, and ending upon the notes maturity on January 15, 2032, unless earlier repurchased or redeemed by Corsicanto or exchanged by the holders. At any time after the issuance of the
2014 Notes and prior to the close of business on the second business day immediately preceding January 15, 2032, holders may exchange their 2014 Notes at their option. If prior to January 15, 2018, a make-whole fundamental change (as
defined in the Indenture) occurs or we elect to redeem the 2014 Notes in connection with certain changes in tax law, in each case as described in the Indenture, and a holder elects to exchange its 2014 Notes in connection with such make-whole
fundamental change or election, as the case may be, such holder may be entitled to an increase in the exchange rate as described in the Indenture. The initial exchange rate is 384.6154 ADSs per $1,000 principal amount of the 2014 Notes (equivalent
to an initial exchange price of approximately $2.60 per ADS, or the Exchange Price), subject to adjustment in certain circumstances. The exchange rate is subject to adjustment from time to time upon the occurrence of certain events, including, but
not limited to, the payment of cash dividends.

As of December 31, 2015, we had cash and cash equivalents of $107.0
million, a decrease of $12.5 million from December 31, 2014. The decrease is primarily due to net cash used in operating activities in support of the commercialization of Vascepa and funding of REDUCE-IT less accounts receivable collections.
Included in our cash balance as of December 31, 2015 was a $15.0 million non-refundable, up-front payment we received upon the execution of our first ex-U.S. licensing agreement in China and surrounding territories, net proceeds of $57.7
million we received from the issuance and sale of our Series A Preference Shares and net proceeds of $11.0 million from the issuance and extinguishment of senior exchangeable notes. We have incurred annual operating losses since our inception and,
as a result, we had an accumulated deficit of $1.1 billion as of December 31, 2015. We believe that our cash and cash equivalents will be sufficient to fund our projected operations for at least the next twelve months. Depending on the level of
cash generated from operations, additional capital may be required to sustain operations. We anticipate that quarterly net cash outflows in future periods will be variable as a result of the timing of certain items, including interest payments and
supply purchases.

The following table summarizes our contractual obligations as of December 31, 2015 and the effects such obligations are expected to have on our liquidity and cash flows in future periods (in
millions):

Payments Due by Period

Total

2016

2017to 2018

2019to 2020

After 2020

Contractual Obligations:

Purchase obligations (1)

$

44.7

$

18.8

$

23.7

$

2.2

$



Operating lease obligations (2)

1.1

0.5

0.6





Interest payment obligationsexchangeable debt (3)

19.0

5.4

10.8

2.8



Total contractual cash obligations

$

64.8

$

24.7

$

35.1

$

5.0

$



(1)

We have Vascepa API supply agreements with three independent companies from which we purchase qualified API supply: Nisshin, Chemport and Finorga SAS, or Novasep. We
also have encapsulation agreements with three FDA-approved commercial API encapsulators for Vascepa manufacturing: Patheon, Inc. (formerly Banner Pharmacaps), Catalent Pharma Solutions, and Capsugel Plöermel SAS, LLC, or Capsugel. Our
agreements with Chemport, Novasep, and Capsugel contain minimum annual purchase levels to enable us to maintain certain supply exclusivity and also contain a provision that any shortfall in the minimum purchase commitments is payable in cash. Each
supplier is required to meet certain performance obligations and the agreements may be terminated by us in the event of non-performance.

Represents scheduled interest payments due under the terms of the 2012 Notes, 2014 and 2015 Notes, assuming that the 2012 Notes remain outstanding through
January 19, 2017 and that the 2014 Notes and 2015 Notes remain outstanding through January 19, 2019 and they have not been exchanged for ADSs. The above table does not reflect the repayment of the notes as they may be exchanged for ADSs.

On December 6, 2012, we entered into an agreement with BioPharma Secured Debt Fund II Holdings Cayman LP,
or BioPharma. Under this agreement, we granted to BioPharma a security interest in future receivables associated with the Vascepa patent rights, in exchange for $100 million received at the closing of the agreement which occurred in December 2012.
We agreed to repay BioPharma up to $150 million of future revenue and receivables. As of December 31, 2015, the net remaining amount to be repaid to BioPharma is $137.3 million. To date, each payment made has reflected the calculated optional
reduction amount as opposed to the contractual threshold payments for each quarterly period. The maximum amount payable under the contractual threshold for 2016 is $47.6 million. The quarterly repayments through December 31, 2015 represented
interest only. In accordance with the agreement with BioPharma, quarterly differences between the calculated optional reduction amounts and the repayment schedule amounts are rescheduled for payment beginning in the second quarter of 2017. Any such
deferred payments will remain subject to continued application of the quarterly ceiling in amounts due established by the calculated threshold based on quarterly Vascepa revenues. No additional interest expense or liability is incurred as a result
of such deferred repayments and no cliff payment of the remaining balance is due except in the event of Company default or Company change of control. The agreement does not expire until $150 million in aggregate has been repaid. We can prepay an
amount equal to $150 million less any previously repaid amount. We currently estimate that Vascepa revenue levels will not be high enough in each quarter to support repayment to BioPharma in accordance with threshold amounts in the repayment
schedule.

We do not enter into financial instruments for trading or speculative purposes. As of December 31, 2015 and
2014, we had no outstanding forward exchange contracts.

In April 2013, we announced the approval by the FDA of the sNDAs covering two of our API
suppliers, Chemport, Inc. and BASF (formerly Equateq Limited). In April 2014, we reached a settlement agreement with BASF under which we received a refund for material purchases of $3.0 million. The Chemport supply agreement provides access to
additional API supply that is incremental to supply from Nisshin, our other existing FDA-approved API supplier. The Chemport agreement includes minimum annual purchase levels enabling us to maintain supply exclusivity. The Chemport agreement also
includes a provision that any shortfall in the minimum purchase commitments is payable in cash, and the maximum amounts payable pursuant to this provision are reflected in the table above. The API supply agreement with BASF terminated in February
2014.

Concurrent with our supply agreement with Chemport entered into in 2011 for the supply of API materials for Vascepa, we
agreed to make a non-controlling minority share equity investment in the supplier of up to $3.3 million. We invested $1.7 million under this agreement in July 2011 and the remaining $1.6 million during 2012. In September 2013, we entered into an
equity sale and purchase agreement between this supplier and a third party in which we agreed to sell approximately $1.3 million of our investment in the supplier to the third party at cost. This transaction closed in the first quarter of 2014. In
August 2014, we entered into a second equity sale and purchase agreement between this supplier and another third party in which we agreed to sell approximately $1.0 million of our remaining investment. This transaction closed in the fourth quarter
of 2014. The remaining carrying amount of $0.2 million as of December 31, 2015 and 2014, respectively, is included in other long term assets and is accounted for under the cost method.

Under the 2004 share repurchase agreement with Laxdale Limited, or Laxdale, upon approval of Vascepa by the FDA on July 26, 2012, we
were required to make a milestone payment to Laxdale of £7.5 million. We made this payment in 2012 and capitalized this Laxdale milestone payment of $11.6 million as a component of other long term assets. This long-term asset is being
amortized over the estimated useful life of the intellectual property we acquired from Laxdale and we recognized amortization expense of $0.6 million during each of the years ended December 31, 2015 and 2014. Also under the Laxdale agreement,
upon receipt of marketing approval in Europe for the first indication for Vascepa (or first indication of any product containing Amarin Neuroscience intellectual property acquired from Laxdale in 2004), we must make an aggregate stock or cash
payment to the former shareholders of Laxdale (at the sole option of each of the sellers) of £7.5 million (approximately $11.1 million as of December 31, 2015). Additionally, upon receipt of a marketing approval in the United States
or Europe for a further indication of Vascepa (or further indication of any other product using Amarin Neuroscience intellectual property), we must make an aggregate stock or cash payment (at the sole option of each of the sellers) of
£5 million (approximately $7.4 million as of December 31, 2015) for each of the two potential market approvals (i.e. £10 million maximum, or approximately $14.8 million as of December 31, 2015).

In addition to the obligations in the table above, we have recorded a liability of $0.1 million for uncertain tax positions that have
been recorded in long-term liabilities as of December 31, 2015. We are not able to reasonably estimate in which future periods these amounts will ultimately be settled.

Off-Balance Sheet Arrangements

We do not have any special purpose entities
or other off-balance sheet arrangements.

Shelf Registration Statement

On March 29, 2014, the universal shelf registration statement on Form S-3 (Registration No. 333-173132) that we had filed with
the SEC on March 29, 2011 expired. On August 7, 2014, we filed with the SEC a new universal shelf registration statement on Form S-3, which provides for the offer, from time to time, of up to $300,000,000 of: ordinary shares, which may be
represented by American Depositary Shares; preference shares, which may be represented by American Depositary Shares; senior or subordinated debt securities; warrants to purchase any of these securities; and any combination of these securities,
individually or as units. The addition of any newly issued equity securities into the market may be dilutive to existing stockholders and new issuances by us or sales by our selling security holders could have an adverse effect on the price of our
securities.

We are exposed to market risks, which include changes in interest rates. We do not use derivative financial instruments in our investment portfolio, and other than in 2013, we enter into no foreign
exchange contracts. Our investments meet high credit quality and diversification standards, as specified in our investment policy.

Foreign Currency Exchange Risk. Our results of operations and cash flows are subject to fluctuations due to changes in the Euro, Sterling and Yen. The majority of cash and cash equivalents and the
majority of our vendor relationships are denominated in U.S. dollars. We therefore believe that the risk of a significant impact on our operating income from foreign currency fluctuations is not substantial. From time to time, we maintain a small
amount of our cash and cash equivalents in Euro and Pound Sterling. We purchase a portion of our supply from Novasep based on a U.S. dollar to Euro exchange rate and as such, remain subject to currency fluctuation risk for such purchases.

Interest Rate Risk. We believe that we are not exposed to significant interest rate risk through market value
fluctuations of balance sheet items (i.e., price risk) or through changes in interest income or expenses (i.e., re-financing or re-investment risk). Interest rate risk mainly arises through interest bearing liabilities and assets. We invest funds
not needed for near-term operating expenses in diversified short-term investments, consisting primarily of investment grade securities. As of December 31, 2015, the fair value of our cash and cash equivalents maturing in one year or less was
$107.0 million and represented 100% of our cash, cash equivalents and investment portfolio. A hypothetical 50 basis point change in interest rates would not result in a material decrease or increase in the fair value of our securities due to the
general short-term nature of our investment portfolio.

Item 8.

Financial Statements and Supplementary Data

Our consolidated financial statements are annexed to this report beginning on page F-1.

Item 9.

Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

None.

Item 9A.

Controls and Procedures

Evaluation of Disclosure Controls and Procedures

We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in the reports that we file or submit under the Securities Exchange Act of 1934, as
amended (the Exchange Act), is (1) recorded, processed, summarized, and reported within the time periods specified in the SECs rules and forms and (2) accumulated and communicated to our management, including our
Principal Executive Officer and Principal Financial Officer, to allow timely decisions regarding required disclosure.

As of
December 31, 2015 (the Evaluation Date), our management, with the participation of our Principal Executive Officer and Principal Financial Officer, evaluated the effectiveness of our disclosure controls and procedures (as defined in
Rules 13a-15(e) and 15d-15(e) under the Exchange Act). Our management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives, and management
necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Our Principal Executive Officer and Principal Financial Officer have concluded based upon the evaluation described above that, as of
the Evaluation Date, our disclosure controls and procedures were effective at the reasonable assurance level.

Managements Report on
Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal
control over financial reporting for our company. Internal control over financial reporting is defined in Rules 13a-15(f) and 15(d)-15(f)

promulgated under the Exchange Act as a process designed by, or under the supervision of, our Principal Executive Officer and Principal Financial Officer and effected by our board of directors,
management, and other personnel to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles and
includes those policies and procedures that:



pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and disposition of our assets;



provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally
accepted accounting principles;



provide reasonable assurance that our receipts and expenditures are being made only in accordance with authorization of our management and directors;
and



provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of our assets that could have a
material effect on the financial statements.

Because of inherent limitations, internal controls over
financial reporting may not prevent or detect misstatements. Projections of any evaluation of effectiveness to future periods are subject to the risks that controls may become inadequate because of changes in conditions or that the degree of
compliance with the policies or procedures may deteriorate.

Our management, including our Principal Executive Officer and
Principal Financial Officer, has conducted an evaluation of the effectiveness of our internal control over financial reporting as of December 31, 2015. In conducting this evaluation, we used the criteria set forth by the Committee of Sponsoring
Organizations of the Treadway Commission (COSO), in Internal Control-Integrated Framework (2013).

Based upon this
evaluation and those criteria, management believes that, as of December 31, 2015, our internal controls over financial reporting were effective.

Ernst & Young LLP, our independent registered public accounting firm, has audited our consolidated financial statements and the effectiveness of our internal control over financial reporting as
of December 31, 2015. This report appears below.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting during the fourth quarter of 2015 that have materially affected, or
are reasonably likely to materially affect, our internal control over financial reporting.

We have
audited Amarin Corporation plcs internal control over financial reporting as of December 31, 2015, based on criteria established in Internal ControlIntegrated Framework issued by the Committee of Sponsoring Organizations of the
Treadway Commission (2013 framework) (the COSO criteria). Amarin Corporation plcs management is responsible for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control
over financial reporting included in the accompanying Report of Management on Internal Controls over Financial Reporting. Our responsibility is to express an opinion on the companys internal control over financial reporting based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States).
Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of
internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we
considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A
companys internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with
generally accepted accounting principles. A companys internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect
the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting
principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of
unauthorized acquisition, use, or disposition of the companys assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject
to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

In our opinion, Amarin Corporation plc maintained, in all material respects, effective internal control over financial reporting as of December 31, 2015, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the consolidated
balance sheets of Amarin Corporation plc as of December 31, 2015 and 2014 and the related consolidated statements of operations, stockholders deficit and cash flows for each of the two years ended December 31, 2015 of Amarin
Corporation plc and our report dated February 25, 2016 expressed an unqualified opinion thereon.

Our policy governing transactions in our securities by our directors, officers and employees permits our officers, directors and certain other persons to enter into trading plans complying with Rule
10b5-1 under the Securities Exchange Act of 1934, as amended. We have been from time to time advised that a number of our directors and employees, including members of our senior management team, and investment funds associated with such persons,
have entered into trading plans in accordance with Rule 10b5-1 and our policy governing transactions in our securities. We undertake no obligation to update or revise the information provided herein, including for revision or termination of an
established trading plan.

On February 23, 2016, Michael J. Farrell, our Vice President, Finance and principal
financial and principal accounting officer, informed us of his resignation, expected to be effective in March 2016. Mr. Farrells resignation did not result from any disagreement regarding our financial reporting or accounting
policies, procedures, estimates or judgments.

In connection with the foregoing, effective as of March 15, 2016,
John F. Thero, our President and Chief Executive Officer, and the former Chief Financial Officer, will serve as our principal financial officer and principal accounting officer on an interim basis. There are no new arrangements or
understandings between Mr. Thero and the company in connection with his service as principal financial officer and principal accounting officer of the company on an interim basis.

We have initiated a search for a full-time Chief Financial Officer that will serve as principal financial officer and principal
accounting officer. It is our intention that the responsibilities of such newly hired Chief Financial Officer will include those currently performed by the current Vice President, Finance position.

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection with our 2016 Annual General Meeting of Shareholders. Such
information is incorporated herein by reference.

Code of Ethics

Our Board of Directors has adopted a code of business conduct and ethics that applies to our directors, officers and employees. There have
been no material modifications to, or waivers from, the provisions of such code. This code is available on the corporate governance section of our website (which is a subsection of the investor relations section of our website) at the following
address: www.amarincorp.com. Any waivers from or amendments to the code will be filed with the SEC on Form 8-K. You may also request a printed copy of the code, without charge, by writing to us at Amarin Pharma, Inc., 1430 Route 206, Bedminster, NJ
07921, Attention: Investor Relations.

Item 11.

Executive Compensation

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection with our 2016 Annual General Meeting of Shareholders. Such
information is incorporated herein by reference.

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection
with our 2016 Annual General Meeting of Shareholders. Such information is incorporated herein by reference.

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection
with our 2016 Annual General Meeting of Shareholders. Such information is incorporated herein by reference.

Item 14.

Principal Accountant Fees and Services

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection with our 2016 Annual General Meeting of Shareholders. Such
information is incorporated herein by reference.

Form of Amended and Restated Deposit Agreement, dated as of November 4, 2011, among the Company, Citibank, N.A., as Depositary, and all holders from time to time of American
Depositary Receipts issued thereunder

Annual Report on Form 10-K for the year ended December 31, 2011, File No. 0-21392, as Exhibit 4.1

February 29, 2012

4.2

Indenture, dated as of January 9, 2012, by and among Corsicanto Limited, the Company and Wells Fargo Bank, National Association, as trustee

Current Report on Form 8-K dated January 9, 2012, File No. 0-21392, as Exhibit 4.1

January 10, 2012

4.3

Indenture, dated as of May 20, 2014, by and among Corsicanto Limited, the Company and Wilmington Trust, National Association, as trustee

Current Report on Form 8-K dated May 15, 2014, File No. 0-21392, as Exhibit 4.1

May 21, 2014

4.4

Form of Ordinary Share certificate

Annual Report on Form 20-F for the year ended December 31, 2002, File No. 0-21392, as Exhibit 2.4

April 24, 2003

4.5

Form of American Depositary Receipt evidencing ADSs

Annual Report on Form 10-K for the year ended December 31, 2011, File No. 0-21392, as Exhibit 4.4

February 29, 2012

4.6

Form of Series A Preference Share Terms

Current Report on Form 8-K dated March 5, 2015, File No. 0-21392, as Exhibit 4.1

March 11, 2015

4.7

Form of Note for 3.50% Notes due 2032

Current Report on Form 8-K dated November 19, 2015, File No. 0-21392, as Exhibit 10.2

November 20, 2015

4.8

Preferred Share Deposit Agreement by and among the Company, Citibank, N.A., as depositary, and all holders and beneficial owners of restricted ADSs issued thereunder

Current Report on Form 8-K dated March 30, 2015, File No. 0-21392, as Exhibit 4.1

March 30, 2015

4.9

Form of American Depositary Receipt evidencing restricted ADSs representing Series A Preference Shares

Current Report on Form 8-K dated March 30, 2015, File No. 0-21392, as Exhibit 4.2

March 30, 2015

10.1

The Company 2002 Stock Option Plan*

Annual Report on Form 20-F for the year ended December 31, 2006, File No. 0-21392, as Exhibit 4.17

Quarterly Report on Form 10-Q for quarterly period ended June 30, 2012, File No. 0-21392, as Exhibit 10.6

August 8, 2008

10.43

Second Amendment to API Commercial Supply Agreement by and between Amarin Pharmaceuticals Ireland Ltd. and Chemport Inc., dated July 19, 2012

Quarterly Report on Form 10-Q for quarterly period ended September 30, 2012, File No. 0-21392, as Exhibit 10.1

November 8, 2012

10.44

Irrevocable License Agreement dated as of April 11, 2011, as amended by the First Amendment to Irrevocable License Agreement dated as of May 9, 2011, each by Amarin Pharmaceuticals
Ireland Ltd. and Bedminster 2 Funding, LLC

Quarterly Report on Form 10-Q for the period ended June 30, 2011, File No. 0-21392, as Exhibit 10.3

August 9, 2011

10.45

Second Amendment to Irrevocable License Agreement, by and between Bedminster 2 Funding, LLC and Amarin Pharmaceuticals Ireland Ltd., dated April 25, 2012

Quarterly Report on Form 10-Q for quarterly period ended June 30, 2012, File No. 0-21392, as Exhibit 10.4

August 8, 2008

10.46

Third Amendment to Irrevocable License Agreement by and between Bedminster 2 Funding, LLC and Amarin Pharmaceuticals Ireland Ltd., dated July 17, 2012

Quarterly Report on Form 10-Q for quarterly period ended June 30, 2012, File No. 0-21392, as Exhibit 10.5

Confidential treatment has been granted with respect to portions of this exhibit pursuant to an application requesting confidential treatment under Rule 24b-2 of the
Securities Exchange Act of 1934. A complete copy of this exhibit, including the redacted terms, has been separately filed with the Securities and Exchange Commission.

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this
report to be signed on its behalf by the undersigned, thereunto duly authorized.

AMARIN CORPORATION PLC

By:

/s/ John F. Thero

John F. Thero

President and Chief Executive Officer

(Principal Executive Officer)

Date: February 25, 2016

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the Registrant and in the capacities and on the date indicated.

Financial statement schedules have been omitted for the reason that the required information is presented in the
consolidated financial statements or notes thereto, the amounts involved are not significant or the schedules are not applicable.

We have audited the
accompanying consolidated balance sheets of Amarin Corporation plc as of December 31, 2015 and 2014, and the related consolidated statements of operations, stockholders deficit and cash flows for each of the two years ended
December 31, 2015. These financial statements are the responsibility of the Companys management. Our responsibility is to express an opinion on these financial statements based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that
we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial
statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for
our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the consolidated financial
position of Amarin Corporation plc at December 31, 2015 and 2014, and the consolidated results of its operations and its cash flows for each of the two years in the period ended December 31, 2015, in conformity with U.S. generally accepted
accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United
States), Amarin Corporation plcs internal control over financial reporting as of December 31, 2015, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway
Commission (2013 framework) and our report dated February 25, 2016 expressed an unqualified opinion thereon.

As discussed in Note 11 to
the consolidated financial statements, the Company changed the classification of all deferred tax assets and liabilities to noncurrent on the balance sheet as a result of the adoption of the amendments to the FASB Accounting Standards Codification
resulting from Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes, effective December 31, 2015.

We have audited the accompanying consolidated statements of operations, stockholders deficit, and cash flows for the year ended
December 31, 2013. These consolidated financial statements are the responsibility of the Companys management. Our responsibility is to express an opinion on the consolidated financial statements based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we
plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial
statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for
our opinion.

In our opinion, such consolidated financial statements present fairly, in all material respects, the results of operations and
cash flows of Amarin Corporation plc and subsidiaries for the year ended December 31, 2013, in conformity with accounting principles generally accepted in the United States of America.

Series A Convertible Preferred Stock, £0.05 par, unlimited authorized; 328,184,640 issued and outstanding as of
December 31, 2015 (equivalent to 32,818,464 ordinary shares upon future consolidation and redesignation at a 10:1 ratio); zero shares issued and outstanding as of December 31, 2014